$NTRS
NORTHERN TRUST CORP Stock $ntrs

$ntrs Overview Financials Valuation SEC Filings Company Website

2021 Q3 Form 10-Q Financial Statement

#000007312421000272 Filed on October 26, 2021

Income Statement

Concept	2021 Q3	2020 Q3	2020 Q2
Revenue	$351.3M	$355.4M	$406.3M
YoY Change	-1.15%	-42.75%	-36.54%
Cost Of Revenue	-$15.70M	-$3.000M	$800.0K
YoY Change	423.33%	-102.34%	-99.45%
Gross Profit	$1.634B	$1.485B	$1.506B
YoY Change	10.01%	-3.43%	-0.03%
Gross Profit Margin	465.07%	417.87%	370.69%
Selling, General & Admin	$874.3M	$816.9M	$795.0M
YoY Change	7.03%	2.04%	2.82%
% of Gross Profit	53.51%	55.01%	52.79%
Research & Development
YoY Change
% of Gross Profit
Depreciation & Amortization	$129.0M	$123.9M	$124.8M
YoY Change	4.12%	7.46%	11.03%
% of Gross Profit	7.9%	8.34%	8.29%
Operating Expenses	$1.116B	$1.095B	$1.103B
YoY Change	1.87%	6.4%	10.32%
Operating Profit	$518.1M	$389.9M	$403.2M
YoY Change	32.88%	-23.34%	-20.46%
Interest Expense	$4.900M	$26.80M	$34.20M
YoY Change	-81.72%	-86.8%	-84.65%
% of Operating Profit	0.95%	6.87%	8.48%
Other Income/Expense, Net
YoY Change
Pretax Income	$518.1M	$389.9M	$403.2M
YoY Change	32.88%	-23.34%	-20.46%
Income Tax	$122.4M	$95.40M	$89.90M
% Of Pretax Income	23.62%	24.47%	22.3%
Net Earnings	$395.7M	$294.5M	$313.3M
YoY Change	34.36%	-23.43%	-19.54%
Net Earnings / Revenue	112.64%	82.86%	77.11%
Basic Earnings Per Share	$1.81	$1.32	$1.47
Diluted Earnings Per Share	$1.80	$1.32	$1.46
COMMON SHARES
Basic Shares Outstanding	208.1M shares	208.1M shares	208.1M shares
Diluted Shares Outstanding	208.9M shares	208.7M shares	208.6M shares

Balance Sheet

Concept	2021 Q3	2020 Q3	2020 Q2
SHORT-TERM ASSETS
Cash & Short-Term Investments	$63.03B	$64.04B	$59.67B
YoY Change	-1.59%	15.5%	11.4%
Cash & Equivalents	$4.195B	$4.738B	$4.462B
Short-Term Investments	$58.83B	$59.31B	$55.21B
Other Short-Term Assets
YoY Change
Inventory
Prepaid Expenses
Receivables
Other Receivables
Total Short-Term Assets	$4.195B	$4.738B	$4.462B
YoY Change	-11.47%	-5.95%	-16.57%
LONG-TERM ASSETS
Property, Plant & Equipment	$493.6M	$510.0M	$501.0M
YoY Change	-3.22%	27.34%	22.94%
Goodwill	$705.5M	$698.0M	$690.6M
YoY Change	1.07%	1.57%	1.26%
Intangibles
YoY Change
Long-Term Investments	$112.7B	$102.8B	$101.8B
YoY Change	9.56%	32.85%	26.24%
Other Assets
YoY Change
Total Long-Term Assets	$164.9B	$147.3B	$147.0B
YoY Change	11.91%	23.49%	21.26%
TOTAL ASSETS
Total Short-Term Assets	$4.195B	$4.738B	$4.462B
Total Long-Term Assets	$164.9B	$147.3B	$147.0B
Total Assets	$169.1B	$152.1B	$151.4B
YoY Change	11.18%	22.3%	19.66%
SHORT-TERM LIABILITIES
YoY Change
Accounts Payable
YoY Change
Accrued Expenses
YoY Change
Deferred Revenue
YoY Change
Short-Term Debt	$142.5B	$125.1B	$122.8B
YoY Change	13.94%	27.97%	21.92%
Long-Term Debt Due	$5.617B	$5.772B	$7.478B
YoY Change	-2.68%	-26.0%	-3.71%
Total Short-Term Liabilities	$148.1B	$130.8B	$130.3B
YoY Change	13.21%	23.33%	19.55%
LONG-TERM LIABILITIES
Long-Term Debt	$3.966B	$5.129B	$5.145B
YoY Change	-22.67%	27.11%	28.92%
Other Long-Term Liabilities	$5.105B	$4.539B	$4.622B
YoY Change	12.47%	32.45%	66.68%
Total Long-Term Liabilities	$9.071B	$9.668B	$9.767B
YoY Change	-6.17%	29.56%	44.4%
TOTAL LIABILITIES
Total Short-Term Liabilities	$148.1B	$130.8B	$130.3B
Total Long-Term Liabilities	$9.071B	$9.668B	$9.767B
Total Liabilities	$157.2B	$140.5B	$140.1B
YoY Change	11.87%	23.74%	21.0%
SHAREHOLDERS EQUITY
Retained Earnings	$12.86B	$12.12B	$11.99B
YoY Change	6.14%	5.92%	6.8%
Common Stock	$408.6M	$408.6M	$408.6M
YoY Change	0.0%	0.0%	0.0%
Preferred Stock
YoY Change
Treasury Stock (at cost)	$3.306B	$3.219B	$3.222B
YoY Change	2.71%	13.38%	25.62%
Treasury Stock Shares	37.51M shares	37.05M shares	37.08M shares
Shareholders Equity	$11.90B	$11.58B	$11.38B
YoY Change
Total Liabilities & Shareholders Equity	$169.1B	$152.1B	$151.4B
YoY Change	11.18%	22.3%	19.66%

Cashflow Statement

Concept	2021 Q3	2020 Q3	2020 Q2
OPERATING ACTIVITIES
Net Income	$395.7M	$294.5M	$313.3M
YoY Change	34.36%	-23.43%	-19.54%
Depreciation, Depletion And Amortization	$129.0M	$123.9M	$124.8M
YoY Change	4.12%	7.46%	11.03%
Cash From Operating Activities	$481.8M	-$77.90M	-$386.5M
YoY Change	-718.49%	-113.5%	-555.78%
INVESTING ACTIVITIES
Capital Expenditures	-$135.3M	-$125.7M	-$132.0M
YoY Change	7.64%	6.53%	-9.28%
Acquisitions
YoY Change
Other Investing Activities	$2.555B	$1.303B	$7.341B
YoY Change	96.18%	-27.03%	-277.71%
Cash From Investing Activities	$2.420B	$1.177B	$7.209B
YoY Change	105.64%	-29.41%	-268.58%
FINANCING ACTIVITIES
Cash Dividend Paid
YoY Change
Common Stock Issuance & Retirement, Net
YoY Change
Debt Paid & Issued, Net
YoY Change
Cash From Financing Activities	-3.465B	-838.3M	-11.84B
YoY Change	313.35%	-66.25%	-367.15%
NET CHANGE
Cash From Operating Activities	481.8M	-77.90M	-386.5M
Cash From Investing Activities	2.420B	1.177B	7.209B
Cash From Financing Activities	-3.465B	-838.3M	-11.84B
Net Change In Cash	-563.3M	260.6M	-5.015B
YoY Change	-316.16%	-208.9%	-2193.9%
FREE CASH FLOW
Cash From Operating Activities	$481.8M	-$77.90M	-$386.5M
Capital Expenditures	-$135.3M	-$125.7M	-$132.0M
Free Cash Flow	$617.1M	$47.80M	-$254.5M
YoY Change	1191.0%	-93.12%	-210.51%

Facts In Submission

Frame	Concept Type	Concept / XBRL Key	Value	Unit
	dei	Amendment Flag AmendmentFlag	false
	dei	Document Fiscal Year Focus DocumentFiscalYearFocus	2021
	dei	Document Fiscal Period Focus DocumentFiscalPeriodFocus	Q3
	dei	Entity Central Index Key EntityCentralIndexKey	0000073124
	dei	Current Fiscal Year End Date CurrentFiscalYearEndDate	--12-31
CY2021Q3	us-gaap	Common Stock Par Or Stated Value Per Share CommonStockParOrStatedValuePerShare	1.6667
CY2020Q4	us-gaap	Common Stock Par Or Stated Value Per Share CommonStockParOrStatedValuePerShare	1.6667
CY2019	us-gaap	Accounting Standards Update Extensible List AccountingStandardsUpdateExtensibleList	http://fasb.org/us-gaap/2021-01-31#AccountingStandardsUpdate201613Member
	dei	Document Type DocumentType	10-Q
	dei	Document Quarterly Report DocumentQuarterlyReport	true
	dei	Document Period End Date DocumentPeriodEndDate	2021-09-30
	dei	Document Transition Report DocumentTransitionReport	false
	dei	Entity File Number EntityFileNumber	001-36609
	dei	Entity Registrant Name EntityRegistrantName	NORTHERN TRUST CORPORATION
	dei	Entity Incorporation State Country Code EntityIncorporationStateCountryCode	DE
	dei	Entity Tax Identification Number EntityTaxIdentificationNumber	36-2723087
	dei	Entity Address Address Line1 EntityAddressAddressLine1	50 South LaSalle Street
	dei	Entity Address Postal Zip Code EntityAddressPostalZipCode	60603
	dei	Entity Address City Or Town EntityAddressCityOrTown	Chicago,
	dei	Entity Address State Or Province EntityAddressStateOrProvince	IL
	dei	City Area Code CityAreaCode	312
	dei	Local Phone Number LocalPhoneNumber	630-6000
	dei	Entity Current Reporting Status EntityCurrentReportingStatus	Yes
	dei	Entity Interactive Data Current EntityInteractiveDataCurrent	Yes
	dei	Entity Filer Category EntityFilerCategory	Large Accelerated Filer
	dei	Entity Small Business EntitySmallBusiness	false
	dei	Entity Emerging Growth Company EntityEmergingGrowthCompany	false
	dei	Entity Shell Company EntityShellCompany	false
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CY2021Q3	us-gaap	Professional Fees ProfessionalFees	210700000	USD
CY2020Q3	us-gaap	Professional Fees ProfessionalFees	186000000.0	USD
	us-gaap	Professional Fees ProfessionalFees	625200000	USD
	us-gaap	Professional Fees ProfessionalFees	555000000.0	USD
CY2021Q3	ntrs	Equipment And Software Expense EquipmentAndSoftwareExpense	185200000	USD
CY2020Q3	ntrs	Equipment And Software Expense EquipmentAndSoftwareExpense	170700000	USD
	ntrs	Equipment And Software Expense EquipmentAndSoftwareExpense	540200000	USD
	ntrs	Equipment And Software Expense EquipmentAndSoftwareExpense	497100000	USD
CY2021Q3	us-gaap	Occupancy Net OccupancyNet	53900000	USD
CY2020Q3	us-gaap	Occupancy Net OccupancyNet	51800000	USD
	us-gaap	Occupancy Net OccupancyNet	156900000	USD
	us-gaap	Occupancy Net OccupancyNet	162900000	USD
CY2021Q3	us-gaap	Other Noninterest Expense OtherNoninterestExpense	81200000	USD
CY2020Q3	us-gaap	Other Noninterest Expense OtherNoninterestExpense	127000000.0	USD
	us-gaap	Other Noninterest Expense OtherNoninterestExpense	220400000	USD
	us-gaap	Other Noninterest Expense OtherNoninterestExpense	274600000	USD
CY2021Q3	us-gaap	Noninterest Expense NoninterestExpense	1128700000	USD
CY2020Q3	us-gaap	Noninterest Expense NoninterestExpense	1094700000	USD
	us-gaap	Noninterest Expense NoninterestExpense	3367000000	USD
	us-gaap	Noninterest Expense NoninterestExpense	3197200000	USD
CY2021Q3	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	518100000	USD
CY2020Q3	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	389900000	USD
	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	1500500000	USD
	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	1254200000	USD
CY2021Q3	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	122400000	USD
CY2020Q3	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	95400000	USD
	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	361600000	USD
	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	285800000	USD
CY2021Q3	us-gaap	Net Income Loss NetIncomeLoss	395700000	USD
CY2020Q3	us-gaap	Net Income Loss NetIncomeLoss	294500000	USD
	us-gaap	Net Income Loss NetIncomeLoss	1138900000	USD
	us-gaap	Net Income Loss NetIncomeLoss	968400000	USD
CY2021Q3	us-gaap	Preferred Stock Dividends Income Statement Impact PreferredStockDividendsIncomeStatementImpact	16200000	USD
CY2020Q3	us-gaap	Preferred Stock Dividends Income Statement Impact PreferredStockDividendsIncomeStatementImpact	16200000	USD
	us-gaap	Preferred Stock Dividends Income Statement Impact PreferredStockDividendsIncomeStatementImpact	37100000	USD
	us-gaap	Preferred Stock Dividends Income Statement Impact PreferredStockDividendsIncomeStatementImpact	51500000	USD
CY2021Q3	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	379500000	USD
CY2020Q3	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	278300000	USD
	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	1101800000	USD
	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	916900000	USD
CY2021Q3	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.81
CY2020Q3	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.32
	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	5.24
	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	4.35
CY2021Q3	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.80
CY2020Q3	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.32
	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	5.22
	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	4.34
CY2021Q3	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification And Tax Parent OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationAndTaxParent	4600000	USD
	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	208199352	shares
CY2021Q3	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	208116009	shares
CY2020Q3	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	208106190	shares
	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	208351088	shares
CY2021Q3	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	208923306	shares
CY2020Q3	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	208688494	shares
	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	209002530	shares
	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	209023331	shares
CY2021Q3	us-gaap	Net Income Loss NetIncomeLoss	395700000	USD
CY2020Q3	us-gaap	Net Income Loss NetIncomeLoss	294500000	USD
	us-gaap	Net Income Loss NetIncomeLoss	1138900000	USD
	us-gaap	Net Income Loss NetIncomeLoss	968400000	USD
CY2021Q3	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	-89600000	USD
CY2020Q3	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	33500000	USD
	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	-358400000	USD
	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	551300000	USD
CY2020Q3	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification And Tax Parent OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationAndTaxParent	1300000	USD
	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification And Tax Parent OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationAndTaxParent	2400000	USD
	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification And Tax Parent OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationAndTaxParent	5300000	USD
CY2021Q3	us-gaap	Other Comprehensive Income Loss Foreign Currency Transaction And Translation Adjustment Net Of Tax OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax	3800000	USD
CY2020Q3	us-gaap	Other Comprehensive Income Loss Foreign Currency Transaction And Translation Adjustment Net Of Tax OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax	1800000	USD
	us-gaap	Other Comprehensive Income Loss Foreign Currency Transaction And Translation Adjustment Net Of Tax OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax	10900000	USD
	us-gaap	Other Comprehensive Income Loss Foreign Currency Transaction And Translation Adjustment Net Of Tax OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax	29500000	USD
CY2021Q3	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Adjustment Net Of Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax	-500000	USD
CY2020Q3	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Adjustment Net Of Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax	-17500000	USD
	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Adjustment Net Of Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax	-31100000	USD
	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Adjustment Net Of Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax	-33100000	USD
CY2021Q3	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	-80700000	USD
CY2020Q3	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	54100000	USD
	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	-314000000.0	USD
	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	619200000	USD
CY2021Q3	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	315000000.0	USD
CY2020Q3	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	348600000	USD
	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	824900000	USD
	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	1587600000	USD
CY2020Q4	us-gaap	Stockholders Equity StockholdersEquity	11688300000	USD
CY2021Q1	us-gaap	Net Income Loss NetIncomeLoss	375100000	USD
CY2021Q1	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	-362100000	USD
CY2021Q1	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.70
CY2021Q1	us-gaap	Dividends Common Stock DividendsCommonStock	151000000.0	USD
CY2021Q1	us-gaap	Dividends Preferred Stock DividendsPreferredStock	16200000	USD
CY2021Q1	us-gaap	Stock Issued During Period Value Share Based Compensation StockIssuedDuringPeriodValueShareBasedCompensation	59400000	USD
CY2021Q1	us-gaap	Treasury Stock Value Acquired Cost Method TreasuryStockValueAcquiredCostMethod	135600000	USD
CY2021Q1	us-gaap	Stockholders Equity StockholdersEquity	11457900000	USD
CY2021Q2	us-gaap	Net Income Loss NetIncomeLoss	368100000	USD
CY2021Q2	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	128800000	USD
CY2021Q2	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.70
CY2021Q2	us-gaap	Dividends Common Stock DividendsCommonStock	148100000	USD
CY2021Q2	us-gaap	Dividends Preferred Stock DividendsPreferredStock	4700000	USD
CY2021Q2	us-gaap	Stock Issued During Period Value Share Based Compensation StockIssuedDuringPeriodValueShareBasedCompensation	51200000	USD
CY2021Q2	us-gaap	Treasury Stock Value Acquired Cost Method TreasuryStockValueAcquiredCostMethod	30200000	USD
CY2021Q2	us-gaap	Stockholders Equity StockholdersEquity	11823000000	USD
CY2021Q3	us-gaap	Net Income Loss NetIncomeLoss	395700000	USD
CY2021Q3	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	-80700000	USD
CY2021Q3	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.70
CY2021Q3	us-gaap	Dividends Common Stock DividendsCommonStock	148000000.0	USD
CY2021Q3	us-gaap	Dividends Preferred Stock DividendsPreferredStock	16200000	USD
CY2021Q3	us-gaap	Stock Issued During Period Value Share Based Compensation StockIssuedDuringPeriodValueShareBasedCompensation	25000000.0	USD
CY2021Q3	us-gaap	Treasury Stock Value Acquired Cost Method TreasuryStockValueAcquiredCostMethod	100000000.0	USD
CY2021Q3	us-gaap	Stockholders Equity StockholdersEquity	11898800000	USD
CY2019Q4	us-gaap	Stockholders Equity StockholdersEquity	11091000000	USD
CY2020Q1	us-gaap	Net Income Loss NetIncomeLoss	360600000	USD
CY2020Q1	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	239700000	USD
CY2020Q1	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.70
CY2020Q1	us-gaap	Dividends Common Stock DividendsCommonStock	148600000	USD
CY2020Q1	us-gaap	Dividends Preferred Stock DividendsPreferredStock	19000000.0	USD
CY2020Q1	us-gaap	Stock Redeemed Or Called During Period Value StockRedeemedOrCalledDuringPeriodValue	400000000.0	USD
CY2020Q1	us-gaap	Stock Issued During Period Value Share Based Compensation StockIssuedDuringPeriodValueShareBasedCompensation	62900000	USD
CY2020Q1	us-gaap	Treasury Stock Value Acquired Cost Method TreasuryStockValueAcquiredCostMethod	296800000	USD
CY2020Q1	us-gaap	Stockholders Equity StockholdersEquity	10879700000	USD
CY2020Q2	us-gaap	Net Income Loss NetIncomeLoss	313300000	USD
CY2020Q2	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	325400000	USD
CY2020Q2	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.70
CY2020Q2	us-gaap	Dividends Common Stock DividendsCommonStock	148200000	USD
CY2020Q2	us-gaap	Dividends Preferred Stock DividendsPreferredStock	4800000	USD
CY2020Q2	us-gaap	Stock Issued During Period Value Share Based Compensation StockIssuedDuringPeriodValueShareBasedCompensation	17000000.0	USD
CY2020Q2	us-gaap	Treasury Stock Value Acquired Cost Method TreasuryStockValueAcquiredCostMethod	200000	USD
CY2020Q2	us-gaap	Stockholders Equity StockholdersEquity	11382200000	USD
CY2020Q3	us-gaap	Net Income Loss NetIncomeLoss	294500000	USD
CY2020Q3	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	54100000	USD
CY2020Q3	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.70
CY2020Q3	us-gaap	Dividends Common Stock DividendsCommonStock	148400000	USD
CY2020Q3	us-gaap	Dividends Preferred Stock DividendsPreferredStock	16200000	USD
CY2020Q3	us-gaap	Stock Issued During Period Value Share Based Compensation StockIssuedDuringPeriodValueShareBasedCompensation	14400000	USD
CY2020Q3	us-gaap	Treasury Stock Value Acquired Cost Method TreasuryStockValueAcquiredCostMethod	1500000	USD
CY2020Q3	us-gaap	Stockholders Equity StockholdersEquity	11579100000	USD
	us-gaap	Net Income Loss NetIncomeLoss	1138900000	USD
	us-gaap	Net Income Loss NetIncomeLoss	968400000	USD
	us-gaap	Marketable Securities Gain Loss MarketableSecuritiesGainLoss	0	USD
	us-gaap	Marketable Securities Gain Loss MarketableSecuritiesGainLoss	100000	USD
	us-gaap	Accretion Amortization Of Discounts And Premiums Investments AccretionAmortizationOfDiscountsAndPremiumsInvestments	-75300000	USD
	us-gaap	Accretion Amortization Of Discounts And Premiums Investments AccretionAmortizationOfDiscountsAndPremiumsInvestments	-63300000	USD
	ntrs	Credit Loss Expense Reversal And Available For Sale Allowance For Credit Loss CreditLossExpenseReversalAndAvailableForSaleAllowanceForCreditLoss	-70000000.0	USD
	ntrs	Credit Loss Expense Reversal And Available For Sale Allowance For Credit Loss CreditLossExpenseReversalAndAvailableForSaleAllowanceForCreditLoss	127500000	USD
	us-gaap	Depreciation Amortization And Accretion Net DepreciationAmortizationAndAccretionNet	382800000	USD
	us-gaap	Depreciation Amortization And Accretion Net DepreciationAmortizationAndAccretionNet	372500000	USD
	us-gaap	Pension Contributions PensionContributions	6700000	USD
	us-gaap	Pension Contributions PensionContributions	10600000	USD
	us-gaap	Increase Decrease In Receivables IncreaseDecreaseInReceivables	139300000	USD
	us-gaap	Increase Decrease In Receivables IncreaseDecreaseInReceivables	-47600000	USD
	us-gaap	Increase Decrease In Interest Payable Net IncreaseDecreaseInInterestPayableNet	3800000	USD
	us-gaap	Increase Decrease In Interest Payable Net IncreaseDecreaseInInterestPayableNet	-5000000.0	USD
	us-gaap	Increase Decrease In Derivative Assets IncreaseDecreaseInDerivativeAssets	2101200000	USD
	us-gaap	Increase Decrease In Derivative Assets IncreaseDecreaseInDerivativeAssets	937200000	USD
	us-gaap	Increase Decrease In Other Operating Capital Net IncreaseDecreaseInOtherOperatingCapitalNet	-30500000	USD
	us-gaap	Increase Decrease In Other Operating Capital Net IncreaseDecreaseInOtherOperatingCapitalNet	205900000	USD
	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	-685900000	USD
	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	420500000	USD
	us-gaap	Increase Decrease In Federal Funds Sold IncreaseDecreaseInFederalFundsSold	0	USD
	us-gaap	Increase Decrease In Federal Funds Sold IncreaseDecreaseInFederalFundsSold	5000000.0	USD
	us-gaap	Proceeds From Payments For Securities Purchased Under Agreements To Resell ProceedsFromPaymentsForSecuritiesPurchasedUnderAgreementsToResell	711200000	USD
	us-gaap	Proceeds From Payments For Securities Purchased Under Agreements To Resell ProceedsFromPaymentsForSecuritiesPurchasedUnderAgreementsToResell	-722900000	USD
	us-gaap	Proceeds From Payments For In Interest Bearing Deposits In Banks ProceedsFromPaymentsForInInterestBearingDepositsInBanks	1371000000	USD
	us-gaap	Proceeds From Maturities Prepayments And Calls Of Held To Maturity Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfHeldToMaturitySecurities	23901200000	USD
	us-gaap	Proceeds From Payments For In Interest Bearing Deposits In Banks ProceedsFromPaymentsForInInterestBearingDepositsInBanks	2194900000	USD
	ntrs	Payments For Proceeds From Federal Reserve And Foreign Central Bank Deposits PaymentsForProceedsFromFederalReserveAndForeignCentralBankDeposits	-4689000000	USD
	ntrs	Payments For Proceeds From Federal Reserve And Foreign Central Bank Deposits PaymentsForProceedsFromFederalReserveAndForeignCentralBankDeposits	4592300000	USD
	us-gaap	Payments To Acquire Held To Maturity Securities PaymentsToAcquireHeldToMaturitySecurities	40859600000	USD
	us-gaap	Payments To Acquire Held To Maturity Securities PaymentsToAcquireHeldToMaturitySecurities	28474000000	USD
	us-gaap	Proceeds From Maturities Prepayments And Calls Of Held To Maturity Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfHeldToMaturitySecurities	43934800000	USD
	us-gaap	Payments To Acquire Available For Sale Securities Debt PaymentsToAcquireAvailableForSaleSecuritiesDebt	9811600000	USD
	us-gaap	Payments To Acquire Available For Sale Securities Debt PaymentsToAcquireAvailableForSaleSecuritiesDebt	8558600000	USD
	us-gaap	Proceeds From Sale And Maturity Of Available For Sale Securities ProceedsFromSaleAndMaturityOfAvailableForSaleSecurities	6229600000	USD
	us-gaap	Proceeds From Sale And Maturity Of Available For Sale Securities ProceedsFromSaleAndMaturityOfAvailableForSaleSecurities	5761900000	USD
	us-gaap	Payments For Proceeds From Loans And Leases PaymentsForProceedsFromLoansAndLeases	5721500000	USD
	us-gaap	Payments For Proceeds From Loans And Leases PaymentsForProceedsFromLoansAndLeases	1339600000	USD
	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	65000000.0	USD
	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	102600000	USD
	us-gaap	Payments For Software PaymentsForSoftware	278700000	USD
	us-gaap	Payments For Software PaymentsForSoftware	287500000	USD
	ntrs	Net Change In Client Security Settlement Receivables NetChangeInClientSecuritySettlementReceivables	814100000	USD
	ntrs	Net Change In Client Security Settlement Receivables NetChangeInClientSecuritySettlementReceivables	1377300000	USD
	us-gaap	Payments For Proceeds From Other Investing Activities PaymentsForProceedsFromOtherInvestingActivities	-803300000	USD
	us-gaap	Payments For Proceeds From Other Investing Activities PaymentsForProceedsFromOtherInvestingActivities	-477300000	USD
	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	188400000	USD
	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-13114500000	USD
	us-gaap	Increase Decrease In Deposits IncreaseDecreaseInDeposits	-271900000	USD
	us-gaap	Increase Decrease In Deposits IncreaseDecreaseInDeposits	12697800000	USD
	ntrs	Change In Federal Funds Purchased ChangeInFederalFundsPurchased	260000000.0	USD
	ntrs	Change In Federal Funds Purchased ChangeInFederalFundsPurchased	-1650800000	USD
	us-gaap	Proceeds From Payments For In Securities Sold Under Agreements To Repurchase ProceedsFromPaymentsForInSecuritiesSoldUnderAgreementsToRepurchase	533800000	USD
	us-gaap	Proceeds From Payments For In Securities Sold Under Agreements To Repurchase ProceedsFromPaymentsForInSecuritiesSoldUnderAgreementsToRepurchase	-219900000	USD
	us-gaap	Proceeds From Repayments Of Short Term Debt Maturing In Three Months Or Less ProceedsFromRepaymentsOfShortTermDebtMaturingInThreeMonthsOrLess	1609100000	USD
	us-gaap	Proceeds From Repayments Of Short Term Debt Maturing In Three Months Or Less ProceedsFromRepaymentsOfShortTermDebtMaturingInThreeMonthsOrLess	-934000000.0	USD
	us-gaap	Proceeds From Issuance Of Senior Long Term Debt ProceedsFromIssuanceOfSeniorLongTermDebt	0	USD
	us-gaap	Proceeds From Issuance Of Senior Long Term Debt ProceedsFromIssuanceOfSeniorLongTermDebt	993200000	USD
	us-gaap	Repayments Of Long Term Debt RepaymentsOfLongTermDebt	500000000.0	USD
	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect	-194800000	USD
	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect	278300000	USD
	us-gaap	Repayments Of Long Term Debt RepaymentsOfLongTermDebt	0	USD
	us-gaap	Payments For Repurchase Of Preferred Stock And Preference Stock PaymentsForRepurchaseOfPreferredStockAndPreferenceStock	0	USD
	us-gaap	Payments For Repurchase Of Preferred Stock And Preference Stock PaymentsForRepurchaseOfPreferredStockAndPreferenceStock	400000000.0	USD
	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	265800000	USD
	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	298500000	USD
	us-gaap	Proceeds From Stock Options Exercised ProceedsFromStockOptionsExercised	48800000	USD
	us-gaap	Proceeds From Stock Options Exercised ProceedsFromStockOptionsExercised	10700000	USD
	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	437800000	USD
	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	438800000	USD
	us-gaap	Payments Of Dividends Preferred Stock And Preference Stock PaymentsOfDividendsPreferredStockAndPreferenceStock	25600000	USD
	us-gaap	Payments Of Dividends Preferred Stock And Preference Stock PaymentsOfDividendsPreferredStockAndPreferenceStock	29700000	USD
	us-gaap	Proceeds From Payments For Other Financing Activities ProceedsFromPaymentsForOtherFinancingActivities	-600000	USD
	us-gaap	Proceeds From Payments For Other Financing Activities ProceedsFromPaymentsForOtherFinancingActivities	700000	USD
	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	430000000.0	USD
	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	13032300000	USD
	us-gaap	Effect Of Exchange Rate On Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents EffectOfExchangeRateOnCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	-127300000	USD
	us-gaap	Effect Of Exchange Rate On Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents EffectOfExchangeRateOnCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	-60000000.0	USD
	us-gaap	Interest Paid Net InterestPaidNet	17700000	USD
	us-gaap	Interest Paid Net InterestPaidNet	190300000	USD
CY2020Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	4389500000	USD
CY2019Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	4459200000	USD
CY2021Q3	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	4194700000	USD
CY2020Q3	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	4737500000	USD
	us-gaap	Income Taxes Paid IncomeTaxesPaid	267800000	USD
	us-gaap	Income Taxes Paid IncomeTaxesPaid	264500000	USD
	us-gaap	Transfer To Other Real Estate TransferToOtherRealEstate	10100000	USD
	us-gaap	Transfer To Other Real Estate TransferToOtherRealEstate	200000	USD
	us-gaap	Debt Securities Held To Maturity Transfer Amount DebtSecuritiesHeldToMaturityTransferAmount	6864100000	USD
	us-gaap	Debt Securities Held To Maturity Transfer Amount DebtSecuritiesHeldToMaturityTransferAmount	301500000	USD
CY2021Q3	us-gaap	Trading Securities TradingSecurities	200000	USD
CY2020Q4	us-gaap	Trading Securities TradingSecurities	500000	USD
CY2021Q3	us-gaap	Debt Securities Available For Sale Amortized Cost Excluding Accrued Interest After Allowance For Credit Loss DebtSecuritiesAvailableForSaleAmortizedCostExcludingAccruedInterestAfterAllowanceForCreditLoss	37741500000	USD
CY2021Q3	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Gain Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax	444200000	USD
CY2021Q3	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Loss Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax	152800000	USD
CY2021Q3	us-gaap	Debt Securities Available For Sale Excluding Accrued Interest DebtSecuritiesAvailableForSaleExcludingAccruedInterest	38032900000	USD
CY2020Q4	us-gaap	Debt Securities Available For Sale Amortized Cost Excluding Accrued Interest After Allowance For Credit Loss DebtSecuritiesAvailableForSaleAmortizedCostExcludingAccruedInterestAfterAllowanceForCreditLoss	41155700000	USD
CY2020Q4	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Gain Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax	897600000	USD
CY2020Q4	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Loss Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax	31300000	USD
CY2020Q4	us-gaap	Debt Securities Available For Sale Excluding Accrued Interest DebtSecuritiesAvailableForSaleExcludingAccruedInterest	42022000000	USD
CY2021Q3	us-gaap	Available For Sale Securities Debt Maturities Within One Year Amortized Cost AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearAmortizedCost	5429000000	USD
CY2021Q3	us-gaap	Available For Sale Securities Debt Maturities Within One Year Fair Value AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearFairValue	5463600000	USD
CY2021Q3	us-gaap	Available For Sale Securities Debt Maturities After One Through Five Years Amortized Cost AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsAmortizedCost	19368000000	USD
CY2021Q3	us-gaap	Available For Sale Securities Debt Maturities After One Through Five Years Fair Value AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsFairValue	19565400000	USD
CY2021Q3	us-gaap	Available For Sale Securities Debt Maturities After Five Through Ten Years Amortized Cost AvailableForSaleSecuritiesDebtMaturitiesAfterFiveThroughTenYearsAmortizedCost	11381600000	USD
CY2021Q3	us-gaap	Available For Sale Securities Debt Maturities After Five Through Ten Years Fair Value AvailableForSaleSecuritiesDebtMaturitiesAfterFiveThroughTenYearsFairValue	11442400000	USD
CY2021Q3	us-gaap	Available For Sale Securities Debt Maturities After Ten Years Amortized Cost AvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsAmortizedCost	1562900000	USD
CY2021Q3	us-gaap	Available For Sale Securities Debt Maturities After Ten Years Fair Value AvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsFairValue	1561500000	USD
CY2021Q3	us-gaap	Debt Securities Available For Sale Amortized Cost Excluding Accrued Interest After Allowance For Credit Loss DebtSecuritiesAvailableForSaleAmortizedCostExcludingAccruedInterestAfterAllowanceForCreditLoss	37741500000	USD
CY2021Q3	us-gaap	Debt Securities Available For Sale Excluding Accrued Interest DebtSecuritiesAvailableForSaleExcludingAccruedInterest	38032900000	USD
CY2021Q3	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position Less Than12 Months DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12Months	10590200000	USD
CY2021Q3	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position Less Than12 Months Accumulated Loss DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss	147700000	USD
CY2021Q3	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position12 Months Or Longer DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLonger	1312700000	USD
CY2021Q3	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position12 Months Or Longer Accumulated Loss DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss	5100000	USD
CY2021Q3	us-gaap	Debt Securities Available For Sale Unrealized Loss Position DebtSecuritiesAvailableForSaleUnrealizedLossPosition	11902900000	USD
CY2021Q3	us-gaap	Debt Securities Available For Sale Unrealized Loss Position Accumulated Loss DebtSecuritiesAvailableForSaleUnrealizedLossPositionAccumulatedLoss	152800000	USD
CY2020Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position Less Than12 Months DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12Months	2995700000	USD
CY2020Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position Less Than12 Months Accumulated Loss DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss	15300000	USD
CY2020Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position12 Months Or Longer DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLonger	3370900000	USD
CY2020Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position12 Months Or Longer Accumulated Loss DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss	16000000.0	USD
CY2020Q4	us-gaap	Debt Securities Available For Sale Unrealized Loss Position DebtSecuritiesAvailableForSaleUnrealizedLossPosition	6366600000	USD
CY2020Q4	us-gaap	Debt Securities Available For Sale Unrealized Loss Position Accumulated Loss DebtSecuritiesAvailableForSaleUnrealizedLossPositionAccumulatedLoss	31300000	USD
CY2021Q3	ntrs	Number Of Securities Unrealized Losses Position NumberOfSecuritiesUnrealizedLossesPosition	966	investment
CY2021Q3	ntrs	Securities Continuous Unrealized Loss Position Fair Value SecuritiesContinuousUnrealizedLossPositionFairValue	11900000000	USD
CY2021Q3	us-gaap	Debt Securities Available For Sale Unrealized Loss Position Accumulated Loss DebtSecuritiesAvailableForSaleUnrealizedLossPositionAccumulatedLoss	152800000	USD
CY2021Q3	us-gaap	Debt Securities Held To Maturity Excluding Accrued Interest Before Allowance For Credit Loss DebtSecuritiesHeldToMaturityExcludingAccruedInterestBeforeAllowanceForCreditLoss	20797800000	USD
CY2021Q3	us-gaap	Held To Maturity Securities Accumulated Unrecognized Holding Gain HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingGain	54900000	USD
CY2021Q3	us-gaap	Held To Maturity Securities Accumulated Unrecognized Holding Loss HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingLoss	159900000	USD
CY2021Q3	us-gaap	Held To Maturity Securities Fair Value HeldToMaturitySecuritiesFairValue	20692800000	USD
CY2020Q4	us-gaap	Debt Securities Held To Maturity Excluding Accrued Interest Before Allowance For Credit Loss DebtSecuritiesHeldToMaturityExcludingAccruedInterestBeforeAllowanceForCreditLoss	17791100000	USD
CY2020Q4	us-gaap	Held To Maturity Securities Accumulated Unrecognized Holding Gain HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingGain	84300000	USD
CY2020Q4	us-gaap	Held To Maturity Securities Accumulated Unrecognized Holding Loss HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingLoss	78000000.0	USD
CY2020Q4	us-gaap	Held To Maturity Securities Fair Value HeldToMaturitySecuritiesFairValue	17797400000	USD
CY2021Q3	us-gaap	Debt Securities Held To Maturity Excluding Accrued Interest Before Allowance For Credit Loss DebtSecuritiesHeldToMaturityExcludingAccruedInterestBeforeAllowanceForCreditLoss	20800000000	USD
CY2021Q3	us-gaap	Held To Maturity Securities Debt Maturities Within One Year Net Carrying Amount HeldToMaturitySecuritiesDebtMaturitiesWithinOneYearNetCarryingAmount	5808900000	USD
CY2021Q3	us-gaap	Held To Maturity Securities Debt Maturities Within One Year Fair Value HeldToMaturitySecuritiesDebtMaturitiesWithinOneYearFairValue	5806600000	USD
CY2021Q3	us-gaap	Held To Maturity Securities Debt Maturities After One Through Five Years Net Carrying Amount HeldToMaturitySecuritiesDebtMaturitiesAfterOneThroughFiveYearsNetCarryingAmount	9692300000	USD
CY2021Q3	us-gaap	Held To Maturity Securities Debt Maturities After One Through Five Years Fair Value HeldToMaturitySecuritiesDebtMaturitiesAfterOneThroughFiveYearsFairValue	9683200000	USD
CY2021Q3	us-gaap	Held To Maturity Securities Debt Maturities After Five Through Ten Years Net Carrying Amount HeldToMaturitySecuritiesDebtMaturitiesAfterFiveThroughTenYearsNetCarryingAmount	4243000000	USD
CY2021Q3	us-gaap	Held To Maturity Securities Debt Maturities After Five Through Ten Years Fair Value HeldToMaturitySecuritiesDebtMaturitiesAfterFiveThroughTenYearsFairValue	4202300000	USD
CY2021Q3	us-gaap	Held To Maturity Securities Debt Maturities After Ten Years Net Carrying Amount HeldToMaturitySecuritiesDebtMaturitiesAfterTenYearsNetCarryingAmount	1053600000	USD
CY2021Q3	us-gaap	Held To Maturity Securities Debt Maturities After Ten Years Fair Value HeldToMaturitySecuritiesDebtMaturitiesAfterTenYearsFairValue	1000700000	USD
CY2021Q3	us-gaap	Debt Securities Held To Maturity Excluding Accrued Interest Before Allowance For Credit Loss DebtSecuritiesHeldToMaturityExcludingAccruedInterestBeforeAllowanceForCreditLoss	20797800000	USD
CY2021Q3	us-gaap	Held To Maturity Securities Fair Value HeldToMaturitySecuritiesFairValue	20692800000	USD
CY2021Q3	ntrs	Held To Maturity Securities Transferred From Available For Sale HeldToMaturitySecuritiesTransferredFromAvailableForSale	0	USD
	ntrs	Held To Maturity Securities Transferred From Available For Sale HeldToMaturitySecuritiesTransferredFromAvailableForSale	6900000000	USD
CY2020Q3	ntrs	Held To Maturity Securities Transferred From Available For Sale HeldToMaturitySecuritiesTransferredFromAvailableForSale	0	USD
	ntrs	Held To Maturity Securities Transferred From Available For Sale HeldToMaturitySecuritiesTransferredFromAvailableForSale	301500000	USD
CY2021Q3	us-gaap	Debt Securities Held To Maturity Excluding Accrued Interest Before Allowance For Credit Loss DebtSecuritiesHeldToMaturityExcludingAccruedInterestBeforeAllowanceForCreditLoss	20797800000	USD
CY2021Q3	ntrs	Debt Securities Held To Maturity Percent Of Portfolio DebtSecuritiesHeldToMaturityPercentOfPortfolio	1
CY2020Q4	us-gaap	Debt Securities Held To Maturity Excluding Accrued Interest Before Allowance For Credit Loss DebtSecuritiesHeldToMaturityExcludingAccruedInterestBeforeAllowanceForCreditLoss	17791100000	USD
CY2020Q4	ntrs	Debt Securities Held To Maturity Percent Of Portfolio DebtSecuritiesHeldToMaturityPercentOfPortfolio	1
	us-gaap	Realized Investment Gains Losses RealizedInvestmentGainsLosses	100000	USD
CY2021Q3	us-gaap	Realized Investment Gains Losses RealizedInvestmentGainsLosses	100000	USD
CY2020Q3	ntrs	Proceedsfrom Saleof Investment Securities ProceedsfromSaleofInvestmentSecurities	0	USD
	ntrs	Proceedsfrom Saleof Investment Securities ProceedsfromSaleofInvestmentSecurities	689200000	USD
	us-gaap	Debt Securities Available For Sale Realized Gain DebtSecuritiesAvailableForSaleRealizedGain	3400000	USD
	us-gaap	Debt Securities Available For Sale Realized Loss DebtSecuritiesAvailableForSaleRealizedLoss	3300000	USD
CY2020Q3	us-gaap	Realized Investment Gains Losses RealizedInvestmentGainsLosses	0	USD
	us-gaap	Realized Investment Gains Losses RealizedInvestmentGainsLosses	100000	USD
CY2021Q3	us-gaap	Financing Receivable Excluding Accrued Interest Before Allowance For Credit Loss FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss	39456600000	USD
CY2020Q4	us-gaap	Financing Receivable Excluding Accrued Interest Before Allowance For Credit Loss FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss	33759700000	USD
CY2021Q3	ntrs	Loans Receivable Overdraft Advances LoansReceivableOverdraftAdvances	2000000000	USD
CY2020Q4	ntrs	Loans Receivable Overdraft Advances LoansReceivableOverdraftAdvances	1100000000	USD
CY2021Q3	ntrs	Overdrawn Demand Deposit Accounts OverdrawnDemandDepositAccounts	6000000	USD
CY2020Q4	ntrs	Overdrawn Demand Deposit Accounts OverdrawnDemandDepositAccounts	26400000	USD
CY2021Q3	us-gaap	Financing Receivable Excluding Accrued Interest Year One Originated Current Fiscal Year FinancingReceivableExcludingAccruedInterestYearOneOriginatedCurrentFiscalYear	7255800000	USD
CY2021Q3	us-gaap	Financing Receivable Excluding Accrued Interest Year Two Originated Fiscal Year Before Current Fiscal Year FinancingReceivableExcludingAccruedInterestYearTwoOriginatedFiscalYearBeforeCurrentFiscalYear	5025100000	USD
CY2021Q3	us-gaap	Financing Receivable Excluding Accrued Interest Year Three Originated Two Years Before Current Fiscal Year FinancingReceivableExcludingAccruedInterestYearThreeOriginatedTwoYearsBeforeCurrentFiscalYear	2888900000	USD
CY2021Q3	us-gaap	Financing Receivable Excluding Accrued Interest Year Four Originated Three Years Before Current Fiscal Year FinancingReceivableExcludingAccruedInterestYearFourOriginatedThreeYearsBeforeCurrentFiscalYear	1053200000	USD
CY2021Q3	us-gaap	Financing Receivable Excluding Accrued Interest Year Five Originated Four Years Before Current Fiscal Year FinancingReceivableExcludingAccruedInterestYearFiveOriginatedFourYearsBeforeCurrentFiscalYear	738800000	USD
CY2021Q3	us-gaap	Financing Receivable Excluding Accrued Interest Originated More Than Five Years Before Current Fiscal Year FinancingReceivableExcludingAccruedInterestOriginatedMoreThanFiveYearsBeforeCurrentFiscalYear	2843400000	USD
CY2021Q3	us-gaap	Financing Receivable Excluding Accrued Interest Revolving FinancingReceivableExcludingAccruedInterestRevolving	19346700000	USD
CY2021Q3	us-gaap	Financing Receivable Excluding Accrued Interest Revolving Converted To Term Loan FinancingReceivableExcludingAccruedInterestRevolvingConvertedToTermLoan	304700000	USD
CY2021Q3	us-gaap	Financing Receivable Excluding Accrued Interest Before Allowance For Credit Loss FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss	39456600000	USD
CY2020Q4	us-gaap	Financing Receivable Excluding Accrued Interest Year One Originated Current Fiscal Year FinancingReceivableExcludingAccruedInterestYearOneOriginatedCurrentFiscalYear	7448600000	USD
CY2020Q4	us-gaap	Financing Receivable Excluding Accrued Interest Year Two Originated Fiscal Year Before Current Fiscal Year FinancingReceivableExcludingAccruedInterestYearTwoOriginatedFiscalYearBeforeCurrentFiscalYear	3667900000	USD
CY2020Q4	us-gaap	Financing Receivable Excluding Accrued Interest Year Three Originated Two Years Before Current Fiscal Year FinancingReceivableExcludingAccruedInterestYearThreeOriginatedTwoYearsBeforeCurrentFiscalYear	1352600000	USD
CY2020Q4	us-gaap	Financing Receivable Excluding Accrued Interest Year Four Originated Three Years Before Current Fiscal Year FinancingReceivableExcludingAccruedInterestYearFourOriginatedThreeYearsBeforeCurrentFiscalYear	1123100000	USD
CY2020Q4	us-gaap	Financing Receivable Excluding Accrued Interest Year Five Originated Four Years Before Current Fiscal Year FinancingReceivableExcludingAccruedInterestYearFiveOriginatedFourYearsBeforeCurrentFiscalYear	1254800000	USD
CY2020Q4	us-gaap	Financing Receivable Excluding Accrued Interest Originated More Than Five Years Before Current Fiscal Year FinancingReceivableExcludingAccruedInterestOriginatedMoreThanFiveYearsBeforeCurrentFiscalYear	3128500000	USD
CY2020Q4	us-gaap	Financing Receivable Excluding Accrued Interest Revolving FinancingReceivableExcludingAccruedInterestRevolving	15453600000	USD
CY2020Q4	us-gaap	Financing Receivable Excluding Accrued Interest Revolving Converted To Term Loan FinancingReceivableExcludingAccruedInterestRevolvingConvertedToTermLoan	330600000	USD
CY2020Q4	us-gaap	Financing Receivable Excluding Accrued Interest Before Allowance For Credit Loss FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss	33759700000	USD
CY2021Q3	ntrs	Financing Receivable Accrual FinancingReceivableAccrual	39315600000	USD
CY2021Q3	us-gaap	Financing Receivable Recorded Investment Nonaccrual Status FinancingReceivableRecordedInvestmentNonaccrualStatus	141000000.0	USD
CY2021Q3	us-gaap	Financing Receivable Excluding Accrued Interest Before Allowance For Credit Loss FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss	39456600000	USD
CY2021Q3	us-gaap	Financing Receivable Nonaccrual No Allowance FinancingReceivableNonaccrualNoAllowance	115700000	USD
CY2021Q3	us-gaap	Other Real Estate And Foreclosed Assets OtherRealEstateAndForeclosedAssets	200000	USD
CY2021Q3	ntrs	Financing Receivable Nonaccrual Including Other Real Estate Owned FinancingReceivableNonaccrualIncludingOtherRealEstateOwned	141200000	USD
CY2020Q4	ntrs	Financing Receivable Accrual FinancingReceivableAccrual	33628000000	USD
CY2020Q4	us-gaap	Financing Receivable Recorded Investment Nonaccrual Status FinancingReceivableRecordedInvestmentNonaccrualStatus	131700000	USD
CY2020Q4	us-gaap	Financing Receivable Excluding Accrued Interest Before Allowance For Credit Loss FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss	33759700000	USD
CY2020Q4	us-gaap	Financing Receivable Nonaccrual No Allowance FinancingReceivableNonaccrualNoAllowance	98100000	USD
CY2020Q4	us-gaap	Other Real Estate And Foreclosed Assets OtherRealEstateAndForeclosedAssets	700000	USD
CY2020Q4	ntrs	Financing Receivable Nonaccrual Including Other Real Estate Owned FinancingReceivableNonaccrualIncludingOtherRealEstateOwned	132400000	USD
CY2021Q3	us-gaap	Financing Receivable Nonaccrual Interest Income FinancingReceivableNonaccrualInterestIncome	1500000	USD
	ntrs	Loans And Leases Receivable Non Performing Loans Interest That Would Have Been Recognized LoansAndLeasesReceivableNonPerformingLoansInterestThatWouldHaveBeenRecognized	3200000	USD
CY2020Q3	us-gaap	Financing Receivable Nonaccrual Interest Income FinancingReceivableNonaccrualInterestIncome	1100000	USD
	us-gaap	Loans And Leases Receivable Impaired Interest Lost On Nonaccrual Loans LoansAndLeasesReceivableImpairedInterestLostOnNonaccrualLoans	3500000	USD
CY2021Q3	ntrs	Financing Receivable Nonaccrual Troubled Debt Restructuring FinancingReceivableNonaccrualTroubledDebtRestructuring	73500000	USD
CY2020Q4	ntrs	Financing Receivable Nonaccrual Troubled Debt Restructuring FinancingReceivableNonaccrualTroubledDebtRestructuring	38900000	USD
CY2021Q3	us-gaap	Financing Receivable Modifications Recorded Investment FinancingReceivableModificationsRecordedInvestment	23300000	USD
CY2020Q4	us-gaap	Financing Receivable Modifications Recorded Investment FinancingReceivableModificationsRecordedInvestment	29300000	USD
CY2021Q3	us-gaap	Loans And Leases Receivable Impaired Commitment To Lend LoansAndLeasesReceivableImpairedCommitmentToLend	200000	USD
CY2020Q4	us-gaap	Loans And Leases Receivable Impaired Commitment To Lend LoansAndLeasesReceivableImpairedCommitmentToLend	10400000	USD
CY2021Q3	us-gaap	Financing Receivable Modifications Number Of Contracts2 FinancingReceivableModificationsNumberOfContracts2	1	contract
CY2021Q3	us-gaap	Financing Receivable Modifications Post Modification Recorded Investment2 FinancingReceivableModificationsPostModificationRecordedInvestment2	200000	USD
CY2021Q3	ntrs	Financing Receivable Troubled Debt Restructuring Postmodification Unpaid Principal Balance FinancingReceivableTroubledDebtRestructuringPostmodificationUnpaidPrincipalBalance	200000	USD
	us-gaap	Financing Receivable Modifications Number Of Contracts2 FinancingReceivableModificationsNumberOfContracts2	16	contract
	us-gaap	Financing Receivable Modifications Post Modification Recorded Investment2 FinancingReceivableModificationsPostModificationRecordedInvestment2	48900000	USD
	ntrs	Financing Receivable Troubled Debt Restructuring Postmodification Unpaid Principal Balance FinancingReceivableTroubledDebtRestructuringPostmodificationUnpaidPrincipalBalance	55300000	USD
CY2020Q3	us-gaap	Financing Receivable Modifications Number Of Contracts2 FinancingReceivableModificationsNumberOfContracts2	11	contract
CY2020Q3	us-gaap	Financing Receivable Modifications Post Modification Recorded Investment2 FinancingReceivableModificationsPostModificationRecordedInvestment2	18400000	USD
CY2020Q3	ntrs	Financing Receivable Troubled Debt Restructuring Postmodification Unpaid Principal Balance FinancingReceivableTroubledDebtRestructuringPostmodificationUnpaidPrincipalBalance	18500000	USD
	us-gaap	Financing Receivable Modifications Number Of Contracts2 FinancingReceivableModificationsNumberOfContracts2	19	contract
	us-gaap	Financing Receivable Modifications Post Modification Recorded Investment2 FinancingReceivableModificationsPostModificationRecordedInvestment2	43600000	USD
	ntrs	Financing Receivable Troubled Debt Restructuring Postmodification Unpaid Principal Balance FinancingReceivableTroubledDebtRestructuringPostmodificationUnpaidPrincipalBalance	44200000	USD
CY2021Q3	us-gaap	Other Real Estate And Foreclosed Assets OtherRealEstateAndForeclosedAssets	200000	USD
CY2021Q3	us-gaap	Mortgage Loans In Process Of Foreclosure Amount MortgageLoansInProcessOfForeclosureAmount	5700000	USD
CY2021Q2	us-gaap	Financing Receivable Allowance For Credit Loss Excluding Accrued Interest FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest	148800000	USD
CY2021Q2	us-gaap	Off Balance Sheet Credit Loss Liability OffBalanceSheetCreditLossLiability	46500000	USD
CY2021Q2	us-gaap	Debt Securities Held To Maturity Allowance For Credit Loss Excluding Accrued Interest DebtSecuritiesHeldToMaturityAllowanceForCreditLossExcludingAccruedInterest	10500000	USD
CY2021Q2	ntrs	Other Financial Assets Allowance For Credit Loss Excluding Accrued Interest OtherFinancialAssetsAllowanceForCreditLossExcludingAccruedInterest	1200000	USD
CY2021Q2	ntrs	Allowance For Credit Loss AllowanceForCreditLoss	207000000.0	USD
CY2021Q3	us-gaap	Financing Receivable Allowance For Credit Losses Write Offs FinancingReceivableAllowanceForCreditLossesWriteOffs	0	USD
CY2021Q3	ntrs	Off Balance Sheet Allowance For Credit Loss Writeoff OffBalanceSheetAllowanceForCreditLossWriteoff	0	USD
CY2021Q3	us-gaap	Debt Securities Held To Maturity Allowance For Credit Loss Writeoff DebtSecuritiesHeldToMaturityAllowanceForCreditLossWriteoff	0	USD
CY2021Q3	ntrs	Other Financial Assets Allowance For Credit Loss Writeoff OtherFinancialAssetsAllowanceForCreditLossWriteoff	0	USD
CY2021Q3	ntrs	Allowance For Credit Loss Writeoff AllowanceForCreditLossWriteoff	0	USD
CY2021Q3	us-gaap	Financing Receivable Allowance For Credit Losses Recovery FinancingReceivableAllowanceForCreditLossesRecovery	1100000	USD
CY2021Q3	ntrs	Off Balance Sheet Credit Loss Liability Recovery OffBalanceSheetCreditLossLiabilityRecovery	0	USD
CY2021Q3	us-gaap	Debt Securities Held To Maturity Allowance For Credit Loss Recovery DebtSecuritiesHeldToMaturityAllowanceForCreditLossRecovery	0	USD
CY2021Q3	ntrs	Other Financial Assets Allowance For Credit Loss Recovery OtherFinancialAssetsAllowanceForCreditLossRecovery	0	USD
CY2021Q3	ntrs	Allowance For Credit Loss Recovery AllowanceForCreditLossRecovery	1100000	USD
CY2021Q3	us-gaap	Financing Receivable Allowance For Credit Loss Writeoff After Recovery FinancingReceivableAllowanceForCreditLossWriteoffAfterRecovery	-1100000	USD
CY2021Q3	ntrs	Off Balance Sheet Credit Loss Liability Changein Present Value Expense Reversal OffBalanceSheetCreditLossLiabilityChangeinPresentValueExpenseReversal	0	USD
CY2021Q3	us-gaap	Debt Securities Held To Maturity Change In Present Value Expense Reversal DebtSecuritiesHeldToMaturityChangeInPresentValueExpenseReversal	0	USD
CY2021Q3	ntrs	Other Financial Assets Change In Present Value Expense Reversal OtherFinancialAssetsChangeInPresentValueExpenseReversal	0	USD
CY2021Q3	us-gaap	Financing Receivable Allowance For Credit Loss Writeoff After Recovery FinancingReceivableAllowanceForCreditLossWriteoffAfterRecovery	-1100000	USD
CY2021Q3	us-gaap	Provision For Loan Losses Expensed ProvisionForLoanLossesExpensed	-6000000.0	USD
CY2021Q3	us-gaap	Off Balance Sheet Credit Loss Liability Credit Loss Expense Reversal OffBalanceSheetCreditLossLiabilityCreditLossExpenseReversal	-6700000	USD
CY2021Q3	us-gaap	Debt Securities Held To Maturity Credit Loss Expense Reversal DebtSecuritiesHeldToMaturityCreditLossExpenseReversal	-100000	USD
CY2021Q3	ntrs	Other Financial Assets Credit Loss Expense Reversal OtherFinancialAssetsCreditLossExpenseReversal	-200000	USD
CY2021Q3	ntrs	Credit Loss Expense Reversal CreditLossExpenseReversal	-13000000.0	USD
CY2021Q3	us-gaap	Financing Receivable Allowance For Credit Loss Excluding Accrued Interest FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest	143900000	USD
CY2021Q3	us-gaap	Off Balance Sheet Credit Loss Liability OffBalanceSheetCreditLossLiability	39800000	USD
CY2021Q3	us-gaap	Debt Securities Held To Maturity Allowance For Credit Loss Excluding Accrued Interest DebtSecuritiesHeldToMaturityAllowanceForCreditLossExcludingAccruedInterest	10400000	USD
CY2021Q3	ntrs	Other Financial Assets Allowance For Credit Loss Excluding Accrued Interest OtherFinancialAssetsAllowanceForCreditLossExcludingAccruedInterest	1000000.0	USD
CY2021Q3	ntrs	Allowance For Credit Loss AllowanceForCreditLoss	195100000	USD
CY2020Q4	us-gaap	Financing Receivable Allowance For Credit Loss Excluding Accrued Interest FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest	190700000	USD
CY2020Q4	us-gaap	Off Balance Sheet Credit Loss Liability OffBalanceSheetCreditLossLiability	61100000	USD
CY2020Q4	us-gaap	Debt Securities Held To Maturity Allowance For Credit Loss Excluding Accrued Interest DebtSecuritiesHeldToMaturityAllowanceForCreditLossExcludingAccruedInterest	7300000	USD
CY2020Q4	ntrs	Other Financial Assets Allowance For Credit Loss Excluding Accrued Interest OtherFinancialAssetsAllowanceForCreditLossExcludingAccruedInterest	800000	USD
CY2020Q4	ntrs	Allowance For Credit Loss AllowanceForCreditLoss	259900000	USD
	us-gaap	Financing Receivable Allowance For Credit Losses Write Offs FinancingReceivableAllowanceForCreditLossesWriteOffs	400000	USD
	ntrs	Off Balance Sheet Allowance For Credit Loss Writeoff OffBalanceSheetAllowanceForCreditLossWriteoff	0	USD
	us-gaap	Debt Securities Held To Maturity Allowance For Credit Loss Writeoff DebtSecuritiesHeldToMaturityAllowanceForCreditLossWriteoff	0	USD
	ntrs	Other Financial Assets Allowance For Credit Loss Writeoff OtherFinancialAssetsAllowanceForCreditLossWriteoff	0	USD
	ntrs	Allowance For Credit Loss Writeoff AllowanceForCreditLossWriteoff	400000	USD
	us-gaap	Financing Receivable Allowance For Credit Losses Recovery FinancingReceivableAllowanceForCreditLossesRecovery	5600000	USD
	ntrs	Off Balance Sheet Credit Loss Liability Recovery OffBalanceSheetCreditLossLiabilityRecovery	0	USD
	us-gaap	Debt Securities Held To Maturity Allowance For Credit Loss Recovery DebtSecuritiesHeldToMaturityAllowanceForCreditLossRecovery	0	USD
	ntrs	Other Financial Assets Allowance For Credit Loss Recovery OtherFinancialAssetsAllowanceForCreditLossRecovery	0	USD
	ntrs	Allowance For Credit Loss Recovery AllowanceForCreditLossRecovery	5600000	USD
	us-gaap	Financing Receivable Allowance For Credit Loss Writeoff After Recovery FinancingReceivableAllowanceForCreditLossWriteoffAfterRecovery	-5200000	USD
	ntrs	Off Balance Sheet Credit Loss Liability Changein Present Value Expense Reversal OffBalanceSheetCreditLossLiabilityChangeinPresentValueExpenseReversal	0	USD
	us-gaap	Debt Securities Held To Maturity Change In Present Value Expense Reversal DebtSecuritiesHeldToMaturityChangeInPresentValueExpenseReversal	0	USD
	ntrs	Other Financial Assets Change In Present Value Expense Reversal OtherFinancialAssetsChangeInPresentValueExpenseReversal	0	USD
	us-gaap	Financing Receivable Allowance For Credit Loss Writeoff After Recovery FinancingReceivableAllowanceForCreditLossWriteoffAfterRecovery	-5200000	USD
	us-gaap	Provision For Loan Losses Expensed ProvisionForLoanLossesExpensed	-52000000.0	USD
	us-gaap	Off Balance Sheet Credit Loss Liability Credit Loss Expense Reversal OffBalanceSheetCreditLossLiabilityCreditLossExpenseReversal	-21300000	USD
	us-gaap	Debt Securities Held To Maturity Credit Loss Expense Reversal DebtSecuritiesHeldToMaturityCreditLossExpenseReversal	3100000	USD
	ntrs	Other Financial Assets Credit Loss Expense Reversal OtherFinancialAssetsCreditLossExpenseReversal	200000	USD
	ntrs	Credit Loss Expense Reversal CreditLossExpenseReversal	-70000000.0	USD
CY2021Q3	us-gaap	Financing Receivable Allowance For Credit Loss Excluding Accrued Interest FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest	143900000	USD
CY2021Q3	us-gaap	Off Balance Sheet Credit Loss Liability OffBalanceSheetCreditLossLiability	39800000	USD
CY2021Q3	us-gaap	Debt Securities Held To Maturity Allowance For Credit Loss Excluding Accrued Interest DebtSecuritiesHeldToMaturityAllowanceForCreditLossExcludingAccruedInterest	10400000	USD
CY2021Q3	ntrs	Other Financial Assets Allowance For Credit Loss Excluding Accrued Interest OtherFinancialAssetsAllowanceForCreditLossExcludingAccruedInterest	1000000.0	USD
CY2021Q3	ntrs	Allowance For Credit Loss AllowanceForCreditLoss	195100000	USD
CY2020Q2	us-gaap	Financing Receivable Allowance For Credit Loss Excluding Accrued Interest FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest	210200000	USD
CY2020Q2	us-gaap	Off Balance Sheet Credit Loss Liability OffBalanceSheetCreditLossLiability	49000000.0	USD
CY2020Q2	us-gaap	Debt Securities Held To Maturity Allowance For Credit Loss Excluding Accrued Interest DebtSecuritiesHeldToMaturityAllowanceForCreditLossExcludingAccruedInterest	6500000	USD
CY2020Q2	ntrs	Other Financial Assets Allowance For Credit Loss Excluding Accrued Interest OtherFinancialAssetsAllowanceForCreditLossExcludingAccruedInterest	1300000	USD
CY2020Q2	ntrs	Allowance For Credit Loss AllowanceForCreditLoss	267000000.0	USD
CY2020Q3	us-gaap	Financing Receivable Allowance For Credit Losses Write Offs FinancingReceivableAllowanceForCreditLossesWriteOffs	800000	USD
CY2020Q3	ntrs	Off Balance Sheet Allowance For Credit Loss Writeoff OffBalanceSheetAllowanceForCreditLossWriteoff	0	USD
CY2020Q3	us-gaap	Debt Securities Held To Maturity Allowance For Credit Loss Writeoff DebtSecuritiesHeldToMaturityAllowanceForCreditLossWriteoff	0	USD
CY2020Q3	ntrs	Other Financial Assets Allowance For Credit Loss Writeoff OtherFinancialAssetsAllowanceForCreditLossWriteoff	0	USD
CY2020Q3	ntrs	Allowance For Credit Loss Writeoff AllowanceForCreditLossWriteoff	800000	USD
CY2020Q3	us-gaap	Financing Receivable Allowance For Credit Losses Recovery FinancingReceivableAllowanceForCreditLossesRecovery	1200000	USD
CY2020Q3	ntrs	Off Balance Sheet Credit Loss Liability Recovery OffBalanceSheetCreditLossLiabilityRecovery	0	USD
CY2020Q3	us-gaap	Debt Securities Held To Maturity Allowance For Credit Loss Recovery DebtSecuritiesHeldToMaturityAllowanceForCreditLossRecovery	0	USD
CY2020Q3	ntrs	Other Financial Assets Allowance For Credit Loss Recovery OtherFinancialAssetsAllowanceForCreditLossRecovery	0	USD
CY2020Q3	ntrs	Allowance For Credit Loss Recovery AllowanceForCreditLossRecovery	1200000	USD
CY2020Q3	us-gaap	Financing Receivable Allowance For Credit Loss Writeoff After Recovery FinancingReceivableAllowanceForCreditLossWriteoffAfterRecovery	-400000	USD
CY2020Q3	ntrs	Off Balance Sheet Credit Loss Liability Changein Present Value Expense Reversal OffBalanceSheetCreditLossLiabilityChangeinPresentValueExpenseReversal	0	USD
CY2020Q3	us-gaap	Debt Securities Held To Maturity Change In Present Value Expense Reversal DebtSecuritiesHeldToMaturityChangeInPresentValueExpenseReversal	0	USD
CY2020Q3	ntrs	Other Financial Assets Change In Present Value Expense Reversal OtherFinancialAssetsChangeInPresentValueExpenseReversal	0	USD
CY2020Q3	us-gaap	Financing Receivable Allowance For Credit Loss Writeoff After Recovery FinancingReceivableAllowanceForCreditLossWriteoffAfterRecovery	-400000	USD
CY2020Q3	us-gaap	Provision For Loan Losses Expensed ProvisionForLoanLossesExpensed	4800000	USD
CY2020Q3	us-gaap	Off Balance Sheet Credit Loss Liability Credit Loss Expense Reversal OffBalanceSheetCreditLossLiabilityCreditLossExpenseReversal	-4100000	USD
CY2020Q3	us-gaap	Debt Securities Held To Maturity Credit Loss Expense Reversal DebtSecuritiesHeldToMaturityCreditLossExpenseReversal	400000	USD
CY2020Q3	ntrs	Other Financial Assets Credit Loss Expense Reversal OtherFinancialAssetsCreditLossExpenseReversal	-600000	USD
CY2020Q3	ntrs	Credit Loss Expense Reversal CreditLossExpenseReversal	500000	USD
CY2020Q3	us-gaap	Financing Receivable Allowance For Credit Loss Excluding Accrued Interest FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest	215400000	USD
CY2020Q3	us-gaap	Off Balance Sheet Credit Loss Liability OffBalanceSheetCreditLossLiability	44900000	USD
CY2020Q3	us-gaap	Debt Securities Held To Maturity Allowance For Credit Loss Excluding Accrued Interest DebtSecuritiesHeldToMaturityAllowanceForCreditLossExcludingAccruedInterest	6900000	USD
CY2020Q3	ntrs	Other Financial Assets Allowance For Credit Loss Excluding Accrued Interest OtherFinancialAssetsAllowanceForCreditLossExcludingAccruedInterest	700000	USD
CY2020Q3	ntrs	Allowance For Credit Loss AllowanceForCreditLoss	267900000	USD
CY2019Q4	us-gaap	Financing Receivable Allowance For Credit Loss Excluding Accrued Interest FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest	104500000	USD
CY2019Q4	us-gaap	Off Balance Sheet Credit Loss Liability OffBalanceSheetCreditLossLiability	19900000	USD
CY2019Q4	us-gaap	Debt Securities Held To Maturity Allowance For Credit Loss Excluding Accrued Interest DebtSecuritiesHeldToMaturityAllowanceForCreditLossExcludingAccruedInterest	0	USD
CY2019Q4	ntrs	Other Financial Assets Allowance For Credit Loss Excluding Accrued Interest OtherFinancialAssetsAllowanceForCreditLossExcludingAccruedInterest	0	USD
CY2019Q4	ntrs	Allowance For Credit Loss AllowanceForCreditLoss	124400000	USD
	us-gaap	Financing Receivable Allowance For Credit Losses Write Offs FinancingReceivableAllowanceForCreditLossesWriteOffs	3000000.0	USD
	ntrs	Off Balance Sheet Allowance For Credit Loss Writeoff OffBalanceSheetAllowanceForCreditLossWriteoff	0	USD
	us-gaap	Debt Securities Held To Maturity Allowance For Credit Loss Writeoff DebtSecuritiesHeldToMaturityAllowanceForCreditLossWriteoff	0	USD
	ntrs	Other Financial Assets Allowance For Credit Loss Writeoff OtherFinancialAssetsAllowanceForCreditLossWriteoff	0	USD
	ntrs	Allowance For Credit Loss Writeoff AllowanceForCreditLossWriteoff	3000000.0	USD
	us-gaap	Financing Receivable Allowance For Credit Losses Recovery FinancingReceivableAllowanceForCreditLossesRecovery	5300000	USD
	ntrs	Off Balance Sheet Credit Loss Liability Recovery OffBalanceSheetCreditLossLiabilityRecovery	0	USD
	us-gaap	Debt Securities Held To Maturity Allowance For Credit Loss Recovery DebtSecuritiesHeldToMaturityAllowanceForCreditLossRecovery	0	USD
	ntrs	Other Financial Assets Allowance For Credit Loss Recovery OtherFinancialAssetsAllowanceForCreditLossRecovery	0	USD
	ntrs	Allowance For Credit Loss Recovery AllowanceForCreditLossRecovery	5300000	USD
	us-gaap	Financing Receivable Allowance For Credit Loss Writeoff After Recovery FinancingReceivableAllowanceForCreditLossWriteoffAfterRecovery	-2300000	USD
	ntrs	Off Balance Sheet Credit Loss Liability Changein Present Value Expense Reversal OffBalanceSheetCreditLossLiabilityChangeinPresentValueExpenseReversal	0	USD
	us-gaap	Debt Securities Held To Maturity Change In Present Value Expense Reversal DebtSecuritiesHeldToMaturityChangeInPresentValueExpenseReversal	0	USD
	ntrs	Other Financial Assets Change In Present Value Expense Reversal OtherFinancialAssetsChangeInPresentValueExpenseReversal	0	USD
	us-gaap	Financing Receivable Allowance For Credit Loss Writeoff After Recovery FinancingReceivableAllowanceForCreditLossWriteoffAfterRecovery	-2300000	USD
	us-gaap	Provision For Loan Losses Expensed ProvisionForLoanLossesExpensed	110800000	USD
	us-gaap	Off Balance Sheet Credit Loss Liability Credit Loss Expense Reversal OffBalanceSheetCreditLossLiabilityCreditLossExpenseReversal	16100000	USD
	us-gaap	Debt Securities Held To Maturity Credit Loss Expense Reversal DebtSecuritiesHeldToMaturityCreditLossExpenseReversal	300000	USD
	ntrs	Other Financial Assets Credit Loss Expense Reversal OtherFinancialAssetsCreditLossExpenseReversal	300000	USD
	ntrs	Credit Loss Expense Reversal CreditLossExpenseReversal	127500000	USD
CY2020Q3	us-gaap	Financing Receivable Allowance For Credit Loss Excluding Accrued Interest FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest	215400000	USD
CY2020Q3	us-gaap	Off Balance Sheet Credit Loss Liability OffBalanceSheetCreditLossLiability	44900000	USD
CY2020Q3	us-gaap	Debt Securities Held To Maturity Allowance For Credit Loss Excluding Accrued Interest DebtSecuritiesHeldToMaturityAllowanceForCreditLossExcludingAccruedInterest	6900000	USD
CY2020Q3	ntrs	Other Financial Assets Allowance For Credit Loss Excluding Accrued Interest OtherFinancialAssetsAllowanceForCreditLossExcludingAccruedInterest	700000	USD
CY2020Q3	ntrs	Allowance For Credit Loss AllowanceForCreditLoss	267900000	USD
CY2021Q3	ntrs	Credit Loss Expense Reversal And Available For Sale Allowance For Credit Loss CreditLossExpenseReversalAndAvailableForSaleAllowanceForCreditLoss	-13000000	USD
CY2020Q3	ntrs	Credit Loss Expense Reversal And Available For Sale Allowance For Credit Loss CreditLossExpenseReversalAndAvailableForSaleAllowanceForCreditLoss	500000	USD
CY2021Q3	us-gaap	Financing Receivable Allowance For Credit Loss Writeoff After Recovery FinancingReceivableAllowanceForCreditLossWriteoffAfterRecovery	-1100000	USD
CY2020Q3	us-gaap	Financing Receivable Allowance For Credit Loss Writeoff After Recovery FinancingReceivableAllowanceForCreditLossWriteoffAfterRecovery	-400000	USD
	ntrs	Credit Loss Expense Reversal And Available For Sale Allowance For Credit Loss CreditLossExpenseReversalAndAvailableForSaleAllowanceForCreditLoss	-70000000	USD
	ntrs	Credit Loss Expense Reversal And Available For Sale Allowance For Credit Loss CreditLossExpenseReversalAndAvailableForSaleAllowanceForCreditLoss	127500000	USD
	us-gaap	Financing Receivable Allowance For Credit Loss Writeoff After Recovery FinancingReceivableAllowanceForCreditLossWriteoffAfterRecovery	-5200000	USD
	us-gaap	Financing Receivable Allowance For Credit Loss Writeoff After Recovery FinancingReceivableAllowanceForCreditLossWriteoffAfterRecovery	-2300000	USD
	ntrs	Financing Receivable Credit Loss Estimate Time Period FinancingReceivableCreditLossEstimateTimePeriod	P2Y
CY2021Q2	us-gaap	Financing Receivable Allowance For Credit Loss Excluding Accrued Interest FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest	148800000	USD
CY2021Q2	us-gaap	Off Balance Sheet Credit Loss Liability OffBalanceSheetCreditLossLiability	46500000	USD
CY2021Q3	us-gaap	Financing Receivable Allowance For Credit Losses Write Offs FinancingReceivableAllowanceForCreditLossesWriteOffs	0	USD
CY2021Q3	ntrs	Off Balance Sheet Allowance For Credit Loss Writeoff OffBalanceSheetAllowanceForCreditLossWriteoff	0	USD
CY2021Q3	us-gaap	Financing Receivable Allowance For Credit Losses Recovery FinancingReceivableAllowanceForCreditLossesRecovery	1100000	USD
CY2021Q3	ntrs	Off Balance Sheet Credit Loss Liability Recovery OffBalanceSheetCreditLossLiabilityRecovery	0	USD
CY2021Q3	us-gaap	Financing Receivable Allowance For Credit Loss Writeoff After Recovery FinancingReceivableAllowanceForCreditLossWriteoffAfterRecovery	-1100000	USD
CY2021Q3	ntrs	Off Balance Sheet Credit Loss Liability Changein Present Value Expense Reversal OffBalanceSheetCreditLossLiabilityChangeinPresentValueExpenseReversal	0	USD
CY2021Q3	us-gaap	Provision For Loan Losses Expensed ProvisionForLoanLossesExpensed	-6000000.0	USD
CY2021Q3	us-gaap	Off Balance Sheet Credit Loss Liability Credit Loss Expense Reversal OffBalanceSheetCreditLossLiabilityCreditLossExpenseReversal	-6700000	USD
CY2021Q3	us-gaap	Financing Receivable Allowance For Credit Loss Excluding Accrued Interest FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest	143900000	USD
CY2021Q3	us-gaap	Off Balance Sheet Credit Loss Liability OffBalanceSheetCreditLossLiability	39800000	USD
	us-gaap	Financing Receivable Allowance For Credit Losses Write Offs FinancingReceivableAllowanceForCreditLossesWriteOffs	400000	USD
	ntrs	Off Balance Sheet Allowance For Credit Loss Writeoff OffBalanceSheetAllowanceForCreditLossWriteoff	0	USD
	us-gaap	Financing Receivable Allowance For Credit Losses Recovery FinancingReceivableAllowanceForCreditLossesRecovery	5600000	USD
	ntrs	Off Balance Sheet Credit Loss Liability Recovery OffBalanceSheetCreditLossLiabilityRecovery	0	USD
	us-gaap	Financing Receivable Allowance For Credit Loss Writeoff After Recovery FinancingReceivableAllowanceForCreditLossWriteoffAfterRecovery	-5200000	USD
	ntrs	Off Balance Sheet Credit Loss Liability Changein Present Value Expense Reversal OffBalanceSheetCreditLossLiabilityChangeinPresentValueExpenseReversal	0	USD
	us-gaap	Provision For Loan Losses Expensed ProvisionForLoanLossesExpensed	-52000000.0	USD
	us-gaap	Off Balance Sheet Credit Loss Liability Credit Loss Expense Reversal OffBalanceSheetCreditLossLiabilityCreditLossExpenseReversal	-21300000	USD
CY2021Q3	us-gaap	Financing Receivable Allowance For Credit Loss Excluding Accrued Interest FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest	143900000	USD
CY2021Q3	us-gaap	Off Balance Sheet Credit Loss Liability OffBalanceSheetCreditLossLiability	39800000	USD
CY2020Q3	us-gaap	Financing Receivable Allowance For Credit Losses Write Offs FinancingReceivableAllowanceForCreditLossesWriteOffs	800000	USD
CY2020Q3	ntrs	Off Balance Sheet Allowance For Credit Loss Writeoff OffBalanceSheetAllowanceForCreditLossWriteoff	0	USD
CY2020Q3	us-gaap	Financing Receivable Allowance For Credit Losses Recovery FinancingReceivableAllowanceForCreditLossesRecovery	1200000	USD
CY2020Q3	ntrs	Off Balance Sheet Credit Loss Liability Recovery OffBalanceSheetCreditLossLiabilityRecovery	0	USD
CY2020Q3	us-gaap	Financing Receivable Allowance For Credit Loss Writeoff After Recovery FinancingReceivableAllowanceForCreditLossWriteoffAfterRecovery	-400000	USD
CY2020Q3	ntrs	Off Balance Sheet Credit Loss Liability Changein Present Value Expense Reversal OffBalanceSheetCreditLossLiabilityChangeinPresentValueExpenseReversal	0	USD
CY2020Q3	us-gaap	Provision For Loan Losses Expensed ProvisionForLoanLossesExpensed	4800000	USD
CY2020Q3	us-gaap	Off Balance Sheet Credit Loss Liability Credit Loss Expense Reversal OffBalanceSheetCreditLossLiabilityCreditLossExpenseReversal	-4100000	USD
CY2020Q3	us-gaap	Financing Receivable Allowance For Credit Loss Excluding Accrued Interest FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest	215400000	USD
CY2020Q3	us-gaap	Off Balance Sheet Credit Loss Liability OffBalanceSheetCreditLossLiability	44900000	USD
CY2019Q4	us-gaap	Financing Receivable Allowance For Credit Loss Excluding Accrued Interest FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest	104500000	USD
CY2019Q4	us-gaap	Off Balance Sheet Credit Loss Liability OffBalanceSheetCreditLossLiability	19900000	USD
	us-gaap	Financing Receivable Allowance For Credit Losses Write Offs FinancingReceivableAllowanceForCreditLossesWriteOffs	3000000.0	USD
	ntrs	Off Balance Sheet Allowance For Credit Loss Writeoff OffBalanceSheetAllowanceForCreditLossWriteoff	0	USD
	us-gaap	Financing Receivable Allowance For Credit Losses Recovery FinancingReceivableAllowanceForCreditLossesRecovery	5300000	USD
	ntrs	Off Balance Sheet Credit Loss Liability Recovery OffBalanceSheetCreditLossLiabilityRecovery	0	USD
	us-gaap	Financing Receivable Allowance For Credit Loss Writeoff After Recovery FinancingReceivableAllowanceForCreditLossWriteoffAfterRecovery	-2300000	USD
	ntrs	Off Balance Sheet Credit Loss Liability Changein Present Value Expense Reversal OffBalanceSheetCreditLossLiabilityChangeinPresentValueExpenseReversal	0	USD
	us-gaap	Provision For Loan Losses Expensed ProvisionForLoanLossesExpensed	110800000	USD
	us-gaap	Off Balance Sheet Credit Loss Liability Credit Loss Expense Reversal OffBalanceSheetCreditLossLiabilityCreditLossExpenseReversal	16100000	USD
CY2020Q3	us-gaap	Financing Receivable Allowance For Credit Loss Excluding Accrued Interest FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest	215400000	USD
CY2020Q3	us-gaap	Off Balance Sheet Credit Loss Liability OffBalanceSheetCreditLossLiability	44900000	USD
CY2021Q3	us-gaap	Financing Receivable Individually Evaluated For Impairment FinancingReceivableIndividuallyEvaluatedForImpairment	192900000	USD
CY2020Q4	us-gaap	Financing Receivable Individually Evaluated For Impairment FinancingReceivableIndividuallyEvaluatedForImpairment	131700000	USD
CY2021Q3	us-gaap	Financing Receivable Collectively Evaluated For Impairment FinancingReceivableCollectivelyEvaluatedForImpairment	39263700000	USD
CY2020Q4	us-gaap	Financing Receivable Collectively Evaluated For Impairment FinancingReceivableCollectivelyEvaluatedForImpairment	33628000000	USD
CY2021Q3	us-gaap	Financing Receivable Excluding Accrued Interest Before Allowance For Credit Loss FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss	39456600000	USD
CY2020Q4	us-gaap	Financing Receivable Excluding Accrued Interest Before Allowance For Credit Loss FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss	33759700000	USD
CY2021Q3	us-gaap	Financing Receivable Allowance For Credit Losses Individually Evaluated For Impairment1 FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment1	10600000	USD
CY2020Q4	us-gaap	Financing Receivable Allowance For Credit Losses Individually Evaluated For Impairment1 FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment1	9100000	USD
CY2021Q3	us-gaap	Financing Receivable Allowance For Credit Losses Collectively Evaluated For Impairment FinancingReceivableAllowanceForCreditLossesCollectivelyEvaluatedForImpairment	133300000	USD
CY2020Q4	us-gaap	Financing Receivable Allowance For Credit Losses Collectively Evaluated For Impairment FinancingReceivableAllowanceForCreditLossesCollectivelyEvaluatedForImpairment	181600000	USD
CY2021Q3	us-gaap	Financing Receivable Allowance For Credit Loss Excluding Accrued Interest FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest	143900000	USD
CY2020Q4	us-gaap	Financing Receivable Allowance For Credit Loss Excluding Accrued Interest FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest	190700000	USD
CY2021Q3	ntrs	Off Balance Sheet Credit Loss Liability Individually Evaluated For Impairment OffBalanceSheetCreditLossLiabilityIndividuallyEvaluatedForImpairment	0	USD
CY2020Q4	ntrs	Off Balance Sheet Credit Loss Liability Individually Evaluated For Impairment OffBalanceSheetCreditLossLiabilityIndividuallyEvaluatedForImpairment	1600000	USD
CY2021Q3	ntrs	Off Balance Sheet Credit Loss Liability Collectively Evaluated For Impairment OffBalanceSheetCreditLossLiabilityCollectivelyEvaluatedForImpairment	39800000	USD
CY2020Q4	ntrs	Off Balance Sheet Credit Loss Liability Collectively Evaluated For Impairment OffBalanceSheetCreditLossLiabilityCollectivelyEvaluatedForImpairment	59500000	USD
CY2021Q3	us-gaap	Off Balance Sheet Credit Loss Liability OffBalanceSheetCreditLossLiability	39800000	USD
CY2020Q4	us-gaap	Off Balance Sheet Credit Loss Liability OffBalanceSheetCreditLossLiability	61100000	USD
CY2021Q3	ntrs	Financing Receivable Allowance For Credit Losses And Off Balance Sheet Credit Loss Liability FinancingReceivableAllowanceForCreditLossesAndOffBalanceSheetCreditLossLiability	183700000	USD
CY2020Q4	ntrs	Financing Receivable Allowance For Credit Losses And Off Balance Sheet Credit Loss Liability FinancingReceivableAllowanceForCreditLossesAndOffBalanceSheetCreditLossLiability	251800000	USD
CY2021Q2	us-gaap	Debt Securities Held To Maturity Allowance For Credit Loss Excluding Accrued Interest DebtSecuritiesHeldToMaturityAllowanceForCreditLossExcludingAccruedInterest	10500000	USD
CY2021Q3	us-gaap	Debt Securities Held To Maturity Credit Loss Expense Reversal DebtSecuritiesHeldToMaturityCreditLossExpenseReversal	-100000	USD
CY2021Q3	us-gaap	Debt Securities Held To Maturity Allowance For Credit Loss Excluding Accrued Interest DebtSecuritiesHeldToMaturityAllowanceForCreditLossExcludingAccruedInterest	10400000	USD
CY2020Q4	us-gaap	Debt Securities Held To Maturity Allowance For Credit Loss Excluding Accrued Interest DebtSecuritiesHeldToMaturityAllowanceForCreditLossExcludingAccruedInterest	7300000	USD
	us-gaap	Debt Securities Held To Maturity Credit Loss Expense Reversal DebtSecuritiesHeldToMaturityCreditLossExpenseReversal	3100000	USD
CY2021Q3	us-gaap	Debt Securities Held To Maturity Allowance For Credit Loss Excluding Accrued Interest DebtSecuritiesHeldToMaturityAllowanceForCreditLossExcludingAccruedInterest	10400000	USD
CY2020Q2	us-gaap	Debt Securities Held To Maturity Allowance For Credit Loss Excluding Accrued Interest DebtSecuritiesHeldToMaturityAllowanceForCreditLossExcludingAccruedInterest	6500000	USD
CY2020Q3	us-gaap	Debt Securities Held To Maturity Credit Loss Expense Reversal DebtSecuritiesHeldToMaturityCreditLossExpenseReversal	400000	USD
CY2020Q3	us-gaap	Debt Securities Held To Maturity Allowance For Credit Loss Excluding Accrued Interest DebtSecuritiesHeldToMaturityAllowanceForCreditLossExcludingAccruedInterest	6900000	USD
CY2019Q4	us-gaap	Debt Securities Held To Maturity Allowance For Credit Loss Excluding Accrued Interest DebtSecuritiesHeldToMaturityAllowanceForCreditLossExcludingAccruedInterest	0	USD
	us-gaap	Debt Securities Held To Maturity Credit Loss Expense Reversal DebtSecuritiesHeldToMaturityCreditLossExpenseReversal	300000	USD
CY2020Q3	us-gaap	Debt Securities Held To Maturity Allowance For Credit Loss Excluding Accrued Interest DebtSecuritiesHeldToMaturityAllowanceForCreditLossExcludingAccruedInterest	6900000	USD
CY2021Q3	ntrs	Other Financial Assets Allowance For Credit Loss Excluding Accrued Interest OtherFinancialAssetsAllowanceForCreditLossExcludingAccruedInterest	1000000	USD
CY2020Q4	ntrs	Other Financial Assets Allowance For Credit Loss Excluding Accrued Interest OtherFinancialAssetsAllowanceForCreditLossExcludingAccruedInterest	800000	USD
CY2021Q3	us-gaap	Financing Receivable Accrued Interest After Allowance For Credit Loss FinancingReceivableAccruedInterestAfterAllowanceForCreditLoss	61700000	USD
CY2020Q4	us-gaap	Financing Receivable Accrued Interest After Allowance For Credit Loss FinancingReceivableAccruedInterestAfterAllowanceForCreditLoss	55300000	USD
CY2021Q3	us-gaap	Debt Securities Held To Maturity Accrued Interest After Allowance For Credit Loss DebtSecuritiesHeldToMaturityAccruedInterestAfterAllowanceForCreditLoss	43200000	USD
CY2020Q4	us-gaap	Debt Securities Held To Maturity Accrued Interest After Allowance For Credit Loss DebtSecuritiesHeldToMaturityAccruedInterestAfterAllowanceForCreditLoss	26500000	USD
CY2021Q3	us-gaap	Debt Securities Available For Sale Accrued Interest After Allowance For Credit Loss DebtSecuritiesAvailableForSaleAccruedInterestAfterAllowanceForCreditLoss	124100000	USD
CY2020Q4	us-gaap	Debt Securities Available For Sale Accrued Interest After Allowance For Credit Loss DebtSecuritiesAvailableForSaleAccruedInterestAfterAllowanceForCreditLoss	153600000	USD
CY2021Q3	ntrs	Other Financial Assets Accrued Interest After Allowance For Credit Loss OtherFinancialAssetsAccruedInterestAfterAllowanceForCreditLoss	1300000	USD
CY2020Q4	ntrs	Other Financial Assets Accrued Interest After Allowance For Credit Loss OtherFinancialAssetsAccruedInterestAfterAllowanceForCreditLoss	1400000	USD
CY2021Q3	us-gaap	Interest Receivable InterestReceivable	230300000	USD
CY2020Q4	us-gaap	Interest Receivable InterestReceivable	236800000	USD
CY2021Q3	us-gaap	Security Owned And Pledged As Collateral Fair Value SecurityOwnedAndPledgedAsCollateralFairValue	54800000000	USD
CY2020Q4	us-gaap	Security Owned And Pledged As Collateral Fair Value SecurityOwnedAndPledgedAsCollateralFairValue	47500000000	USD
CY2021Q3	us-gaap	Financial Instruments Owned And Pledged As Collateral Amount Eligible To Be Repledged By Counterparty FinancialInstrumentsOwnedAndPledgedAsCollateralAmountEligibleToBeRepledgedByCounterparty	589000000	USD
CY2020Q4	us-gaap	Financial Instruments Owned And Pledged As Collateral Amount Eligible To Be Repledged By Counterparty FinancialInstrumentsOwnedAndPledgedAsCollateralAmountEligibleToBeRepledgedByCounterparty	33500000	USD
CY2021Q3	us-gaap	Fair Value Of Securities Received As Collateral That Have Been Resold Or Repledged FairValueOfSecuritiesReceivedAsCollateralThatHaveBeenResoldOrRepledged	415600000	USD
CY2020	us-gaap	Securities Received As Collateral Amount Repledged And Sold SecuritiesReceivedAsCollateralAmountRepledgedAndSold	0	USD
	ntrs	Average Interest Bearing Deposits In Federal Reserve Bank For Reserve Requirements AverageInterestBearingDepositsInFederalReserveBankForReserveRequirements	500000000	USD
CY2020Q4	us-gaap	Goodwill Goodwill	707200000	USD
	us-gaap	Goodwill Acquired During Period GoodwillAcquiredDuringPeriod	4200000	USD
	us-gaap	Goodwill Foreign Currency Translation Gain Loss GoodwillForeignCurrencyTranslationGainLoss	-5900000	USD
CY2021Q3	us-gaap	Goodwill Goodwill	705500000	USD
CY2021Q3	us-gaap	Finite Lived Intangible Assets Gross FiniteLivedIntangibleAssetsGross	208400000	USD
CY2020Q4	us-gaap	Finite Lived Intangible Assets Gross FiniteLivedIntangibleAssetsGross	221300000	USD
CY2021Q3	us-gaap	Finite Lived Intangible Assets Accumulated Amortization FiniteLivedIntangibleAssetsAccumulatedAmortization	112600000	USD
CY2020Q4	us-gaap	Finite Lived Intangible Assets Accumulated Amortization FiniteLivedIntangibleAssetsAccumulatedAmortization	108700000	USD
CY2021Q3	us-gaap	Finite Lived Intangible Assets Net FiniteLivedIntangibleAssetsNet	95800000	USD
CY2020Q4	us-gaap	Finite Lived Intangible Assets Net FiniteLivedIntangibleAssetsNet	112600000	USD
	us-gaap	Number Of Reportable Segments NumberOfReportableSegments	2	segment
CY2021Q3	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	1111000000	USD
CY2020Q3	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	1003800000	USD
CY2021Q3	us-gaap	Foreign Currency Transaction Gain Loss Before Tax ForeignCurrencyTransactionGainLossBeforeTax	66400000	USD
CY2020Q3	us-gaap	Foreign Currency Transaction Gain Loss Before Tax ForeignCurrencyTransactionGainLossBeforeTax	61600000	USD
CY2021Q3	us-gaap	Noninterest Income Other NoninterestIncomeOther	110000000.0	USD
CY2020Q3	us-gaap	Noninterest Income Other NoninterestIncomeOther	91100000	USD
CY2021Q3	us-gaap	Noninterest Income NoninterestIncome	1287400000	USD
CY2020Q3	us-gaap	Noninterest Income NoninterestIncome	1156500000	USD
CY2021Q3	ntrs	Interest Revenue Expense Net Including Fully Taxable Equivalent Adjustment InterestRevenueExpenseNetIncludingFullyTaxableEquivalentAdjustment	357100000	USD
CY2020Q3	ntrs	Interest Revenue Expense Net Including Fully Taxable Equivalent Adjustment InterestRevenueExpenseNetIncludingFullyTaxableEquivalentAdjustment	336500000	USD
CY2021Q3	ntrs	Revenue Including Fully Taxable Equivalent Adjustment RevenueIncludingFullyTaxableEquivalentAdjustment	1644500000	USD
CY2020Q3	ntrs	Revenue Including Fully Taxable Equivalent Adjustment RevenueIncludingFullyTaxableEquivalentAdjustment	1493000000	USD
CY2021Q3	ntrs	Credit Loss Expense Reversal And Available For Sale Allowance For Credit Loss CreditLossExpenseReversalAndAvailableForSaleAllowanceForCreditLoss	-13000000.0	USD
CY2020Q3	ntrs	Credit Loss Expense Reversal And Available For Sale Allowance For Credit Loss CreditLossExpenseReversalAndAvailableForSaleAllowanceForCreditLoss	500000	USD
CY2021Q3	us-gaap	Noninterest Expense NoninterestExpense	1128700000	USD
CY2020Q3	us-gaap	Noninterest Expense NoninterestExpense	1094700000	USD
CY2021Q3	ntrs	Income Loss Before Income Taxes Including Fully Taxable Equivalent Adjustment IncomeLossBeforeIncomeTaxesIncludingFullyTaxableEquivalentAdjustment	528800000	USD
CY2020Q3	ntrs	Income Loss Before Income Taxes Including Fully Taxable Equivalent Adjustment IncomeLossBeforeIncomeTaxesIncludingFullyTaxableEquivalentAdjustment	397800000	USD
CY2021Q3	ntrs	Income Tax Expense Benefit Including Fully Taxable Equivalent Adjustment IncomeTaxExpenseBenefitIncludingFullyTaxableEquivalentAdjustment	133100000	USD
CY2020Q3	ntrs	Income Tax Expense Benefit Including Fully Taxable Equivalent Adjustment IncomeTaxExpenseBenefitIncludingFullyTaxableEquivalentAdjustment	103300000	USD
CY2021Q3	us-gaap	Net Income Loss NetIncomeLoss	395700000	USD
CY2020Q3	us-gaap	Net Income Loss NetIncomeLoss	294500000	USD
CY2021Q3	ntrs	Percentage Of Consolidated Net Income PercentageOfConsolidatedNetIncome	1
CY2020Q3	ntrs	Percentage Of Consolidated Net Income PercentageOfConsolidatedNetIncome	1
CY2021Q3	ntrs	Segment Reporting Information Consolidated Average Assets SegmentReportingInformationConsolidatedAverageAssets	156452800000	USD
CY2020Q3	ntrs	Segment Reporting Information Consolidated Average Assets SegmentReportingInformationConsolidatedAverageAssets	140925400000	USD
CY2021Q2	ntrs	Segment Reporting Information Fully Taxable Equivalent Adjustment SegmentReportingInformationFullyTaxableEquivalentAdjustment	10700000	USD
CY2020Q3	ntrs	Segment Reporting Information Fully Taxable Equivalent Adjustment SegmentReportingInformationFullyTaxableEquivalentAdjustment	7900000	USD
	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	3250100000	USD
	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	2968900000	USD
	us-gaap	Foreign Currency Transaction Gain Loss Before Tax ForeignCurrencyTransactionGainLossBeforeTax	215700000	USD
	us-gaap	Foreign Currency Transaction Gain Loss Before Tax ForeignCurrencyTransactionGainLossBeforeTax	221800000	USD
	us-gaap	Noninterest Income Other NoninterestIncomeOther	309600000	USD
	us-gaap	Noninterest Income Other NoninterestIncomeOther	279400000	USD
	us-gaap	Noninterest Income NoninterestIncome	3775400000	USD
	us-gaap	Noninterest Income NoninterestIncome	3470100000	USD
	ntrs	Interest Revenue Expense Net Including Fully Taxable Equivalent Adjustment InterestRevenueExpenseNetIncludingFullyTaxableEquivalentAdjustment	1047700000	USD
	ntrs	Interest Revenue Expense Net Including Fully Taxable Equivalent Adjustment InterestRevenueExpenseNetIncludingFullyTaxableEquivalentAdjustment	1132500000	USD
	ntrs	Revenue Including Fully Taxable Equivalent Adjustment RevenueIncludingFullyTaxableEquivalentAdjustment	4823100000	USD
	ntrs	Revenue Including Fully Taxable Equivalent Adjustment RevenueIncludingFullyTaxableEquivalentAdjustment	4823100000	USD
	ntrs	Revenue Including Fully Taxable Equivalent Adjustment RevenueIncludingFullyTaxableEquivalentAdjustment	4602600000	USD
	ntrs	Revenue Including Fully Taxable Equivalent Adjustment RevenueIncludingFullyTaxableEquivalentAdjustment	4602600000	USD
	ntrs	Credit Loss Expense Reversal And Available For Sale Allowance For Credit Loss CreditLossExpenseReversalAndAvailableForSaleAllowanceForCreditLoss	-70000000.0	USD
	ntrs	Credit Loss Expense Reversal And Available For Sale Allowance For Credit Loss CreditLossExpenseReversalAndAvailableForSaleAllowanceForCreditLoss	127500000	USD
	us-gaap	Noninterest Expense NoninterestExpense	3367000000	USD
	us-gaap	Noninterest Expense NoninterestExpense	3197200000	USD
	ntrs	Income Loss Before Income Taxes Including Fully Taxable Equivalent Adjustment IncomeLossBeforeIncomeTaxesIncludingFullyTaxableEquivalentAdjustment	1526100000	USD
	ntrs	Income Loss Before Income Taxes Including Fully Taxable Equivalent Adjustment IncomeLossBeforeIncomeTaxesIncludingFullyTaxableEquivalentAdjustment	1277900000	USD
	ntrs	Income Tax Expense Benefit Including Fully Taxable Equivalent Adjustment IncomeTaxExpenseBenefitIncludingFullyTaxableEquivalentAdjustment	387200000	USD
	ntrs	Income Tax Expense Benefit Including Fully Taxable Equivalent Adjustment IncomeTaxExpenseBenefitIncludingFullyTaxableEquivalentAdjustment	309500000	USD
	us-gaap	Net Income Loss NetIncomeLoss	1138900000	USD
	us-gaap	Net Income Loss NetIncomeLoss	968400000	USD
	ntrs	Percentage Of Consolidated Net Income PercentageOfConsolidatedNetIncome	1
	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	-314000000.0	USD
	ntrs	Percentage Of Consolidated Net Income PercentageOfConsolidatedNetIncome	1
	ntrs	Segment Reporting Information Consolidated Average Assets SegmentReportingInformationConsolidatedAverageAssets	154681300000	USD
	ntrs	Segment Reporting Information Consolidated Average Assets SegmentReportingInformationConsolidatedAverageAssets	134645200000	USD
	ntrs	Segment Reporting Information Fully Taxable Equivalent Adjustment SegmentReportingInformationFullyTaxableEquivalentAdjustment	25600000	USD
	ntrs	Segment Reporting Information Fully Taxable Equivalent Adjustment SegmentReportingInformationFullyTaxableEquivalentAdjustment	23700000	USD
CY2021Q3	us-gaap	Preferred Stock Shares Authorized PreferredStockSharesAuthorized	10000000	shares
CY2021Q3	us-gaap	Treasury Stock Shares Acquired TreasuryStockSharesAcquired	859587	shares
CY2021Q3	ntrs	Treasury Stock Sharebased Compensation Shares Acquired TreasuryStockSharebasedCompensationSharesAcquired	11169	shares
CY2021Q3	us-gaap	Treasury Stock Value Acquired Cost Method TreasuryStockValueAcquiredCostMethod	100000000	USD
CY2021Q3	us-gaap	Treasury Stock Acquired Average Cost Per Share TreasuryStockAcquiredAverageCostPerShare	116.34
	us-gaap	Treasury Stock Shares Acquired TreasuryStockSharesAcquired	2511564	shares
	ntrs	Treasury Stock Sharebased Compensation Shares Acquired TreasuryStockSharebasedCompensationSharesAcquired	378346	shares
	us-gaap	Treasury Stock Value Acquired Cost Method TreasuryStockValueAcquiredCostMethod	265800000	USD
	us-gaap	Treasury Stock Acquired Average Cost Per Share TreasuryStockAcquiredAverageCostPerShare	105.84
CY2021Q3	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	-80700000	USD
CY2020Q3	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	54100000	USD
	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	619200000	USD
CY2021Q3	us-gaap	Other Comprehensive Income Loss Before Tax Portion Attributable To Parent OtherComprehensiveIncomeLossBeforeTaxPortionAttributableToParent	-90900000	USD
CY2021Q3	us-gaap	Other Comprehensive Income Loss Tax Portion Attributable To Parent1 OtherComprehensiveIncomeLossTaxPortionAttributableToParent1	-10200000	USD
CY2021Q3	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	-80700000	USD
CY2020Q3	us-gaap	Other Comprehensive Income Loss Before Tax Portion Attributable To Parent OtherComprehensiveIncomeLossBeforeTaxPortionAttributableToParent	46100000	USD
CY2020Q3	us-gaap	Other Comprehensive Income Loss Tax Portion Attributable To Parent1 OtherComprehensiveIncomeLossTaxPortionAttributableToParent1	-8000000.0	USD
CY2020Q3	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	54100000	USD
	us-gaap	Other Comprehensive Income Loss Before Tax Portion Attributable To Parent OtherComprehensiveIncomeLossBeforeTaxPortionAttributableToParent	-393000000.0	USD
	us-gaap	Other Comprehensive Income Loss Tax Portion Attributable To Parent1 OtherComprehensiveIncomeLossTaxPortionAttributableToParent1	-79000000.0	USD
	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	-314000000.0	USD
	us-gaap	Other Comprehensive Income Loss Before Tax Portion Attributable To Parent OtherComprehensiveIncomeLossBeforeTaxPortionAttributableToParent	811700000	USD
	us-gaap	Other Comprehensive Income Loss Tax Portion Attributable To Parent1 OtherComprehensiveIncomeLossTaxPortionAttributableToParent1	192500000	USD
	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	619200000	USD
CY2021Q3	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	208116009	shares
CY2020Q3	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	208106190	shares
	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	208199352	shares
	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	208351088	shares
CY2021Q3	us-gaap	Net Income Loss NetIncomeLoss	395700000	USD
CY2020Q3	us-gaap	Net Income Loss NetIncomeLoss	294500000	USD
	us-gaap	Net Income Loss NetIncomeLoss	1138900000	USD
	us-gaap	Net Income Loss NetIncomeLoss	968400000	USD
CY2021Q3	us-gaap	Preferred Stock Dividends Income Statement Impact PreferredStockDividendsIncomeStatementImpact	16200000	USD
CY2020Q3	us-gaap	Preferred Stock Dividends Income Statement Impact PreferredStockDividendsIncomeStatementImpact	16200000	USD
	us-gaap	Preferred Stock Dividends Income Statement Impact PreferredStockDividendsIncomeStatementImpact	37100000	USD
	us-gaap	Preferred Stock Dividends Income Statement Impact PreferredStockDividendsIncomeStatementImpact	51500000	USD
CY2021Q3	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	379500000	USD
CY2020Q3	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	278300000	USD
	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	1101800000	USD
	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	916900000	USD
CY2021Q3	us-gaap	Undistributed Earnings Loss Allocated To Participating Securities Basic UndistributedEarningsLossAllocatedToParticipatingSecuritiesBasic	3000000.0	USD
CY2020Q3	us-gaap	Undistributed Earnings Loss Allocated To Participating Securities Basic UndistributedEarningsLossAllocatedToParticipatingSecuritiesBasic	3300000	USD
	us-gaap	Undistributed Earnings Loss Allocated To Participating Securities Basic UndistributedEarningsLossAllocatedToParticipatingSecuritiesBasic	9900000	USD
	us-gaap	Undistributed Earnings Loss Allocated To Participating Securities Basic UndistributedEarningsLossAllocatedToParticipatingSecuritiesBasic	10600000	USD
CY2021Q3	ntrs	Net Income Loss Allocated To Common Stockholders Basic NetIncomeLossAllocatedToCommonStockholdersBasic	376500000	USD
CY2020Q3	ntrs	Net Income Loss Allocated To Common Stockholders Basic NetIncomeLossAllocatedToCommonStockholdersBasic	275000000.0	USD
	ntrs	Net Income Loss Allocated To Common Stockholders Basic NetIncomeLossAllocatedToCommonStockholdersBasic	1091900000	USD
	ntrs	Net Income Loss Allocated To Common Stockholders Basic NetIncomeLossAllocatedToCommonStockholdersBasic	906300000	USD
CY2021Q3	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.81
CY2020Q3	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.32
	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	5.24
	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	4.35
CY2021Q3	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	208116009	shares
CY2020Q3	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	208106190	shares
	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	208199352	shares
	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	208351088	shares
CY2021Q3	us-gaap	Incremental Common Shares Attributable To Share Based Payment Arrangements IncrementalCommonSharesAttributableToShareBasedPaymentArrangements	807297	shares
CY2020Q3	us-gaap	Incremental Common Shares Attributable To Share Based Payment Arrangements IncrementalCommonSharesAttributableToShareBasedPaymentArrangements	582304	shares
	us-gaap	Incremental Common Shares Attributable To Share Based Payment Arrangements IncrementalCommonSharesAttributableToShareBasedPaymentArrangements	803178	shares
	us-gaap	Incremental Common Shares Attributable To Share Based Payment Arrangements IncrementalCommonSharesAttributableToShareBasedPaymentArrangements	672243	shares
CY2021Q3	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	208923306	shares
CY2020Q3	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	208688494	shares
	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	209002530	shares
	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	209023331	shares
CY2021Q3	us-gaap	Net Income Loss Available To Common Stockholders Diluted NetIncomeLossAvailableToCommonStockholdersDiluted	376500000	USD
CY2020Q3	us-gaap	Net Income Loss Available To Common Stockholders Diluted NetIncomeLossAvailableToCommonStockholdersDiluted	275000000.0	USD
	us-gaap	Net Income Loss Available To Common Stockholders Diluted NetIncomeLossAvailableToCommonStockholdersDiluted	1091900000	USD
	us-gaap	Net Income Loss Available To Common Stockholders Diluted NetIncomeLossAvailableToCommonStockholdersDiluted	906300000	USD
CY2021Q3	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.80
CY2020Q3	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.32
	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	5.22
	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	4.34
	us-gaap	Antidilutive Securities Excluded From Computation Of Earnings Per Share Amount AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount	0	shares
CY2021Q3	us-gaap	Antidilutive Securities Excluded From Computation Of Earnings Per Share Amount AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount	0	shares
CY2021Q3	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	1111000000	USD
CY2020Q3	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	1003800000	USD
	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	3250100000	USD
	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	2968900000	USD
CY2021Q3	us-gaap	Foreign Currency Transaction Gain Loss Before Tax ForeignCurrencyTransactionGainLossBeforeTax	66400000	USD
CY2020Q3	us-gaap	Foreign Currency Transaction Gain Loss Before Tax ForeignCurrencyTransactionGainLossBeforeTax	61600000	USD
	us-gaap	Foreign Currency Transaction Gain Loss Before Tax ForeignCurrencyTransactionGainLossBeforeTax	215700000	USD
	us-gaap	Foreign Currency Transaction Gain Loss Before Tax ForeignCurrencyTransactionGainLossBeforeTax	221800000	USD
CY2021Q3	ntrs	Treasury Management Fees TreasuryManagementFees	11200000	USD
CY2020Q3	ntrs	Treasury Management Fees TreasuryManagementFees	11600000	USD
	ntrs	Treasury Management Fees TreasuryManagementFees	33700000	USD
	ntrs	Treasury Management Fees TreasuryManagementFees	34000000.0	USD
CY2021Q3	ntrs	Security Commissionsand Trading Income SecurityCommissionsandTradingIncome	36500000	USD
CY2020Q3	ntrs	Security Commissionsand Trading Income SecurityCommissionsandTradingIncome	26000000.0	USD
	ntrs	Security Commissionsand Trading Income SecurityCommissionsandTradingIncome	104300000	USD
	ntrs	Security Commissionsand Trading Income SecurityCommissionsandTradingIncome	100900000	USD
CY2021Q3	us-gaap	Other Operating Income OtherOperatingIncome	62300000	USD
CY2020Q3	us-gaap	Other Operating Income OtherOperatingIncome	53500000	USD
	us-gaap	Other Operating Income OtherOperatingIncome	171600000	USD
	us-gaap	Other Operating Income OtherOperatingIncome	144400000	USD
CY2021Q3	us-gaap	Marketable Securities Gain Loss MarketableSecuritiesGainLoss	0	USD
CY2020Q3	us-gaap	Marketable Securities Gain Loss MarketableSecuritiesGainLoss	0	USD
	us-gaap	Marketable Securities Gain Loss MarketableSecuritiesGainLoss	0	USD
	us-gaap	Marketable Securities Gain Loss MarketableSecuritiesGainLoss	100000	USD
CY2021Q3	ntrs	Other Noninterest Income OtherNoninterestIncome	176400000	USD
CY2020Q3	ntrs	Other Noninterest Income OtherNoninterestIncome	152700000	USD
	ntrs	Other Noninterest Income OtherNoninterestIncome	525300000	USD
	ntrs	Other Noninterest Income OtherNoninterestIncome	501200000	USD
CY2021Q3	us-gaap	Noninterest Income NoninterestIncome	1287400000	USD
CY2020Q3	us-gaap	Noninterest Income NoninterestIncome	1156500000	USD
	us-gaap	Noninterest Income NoninterestIncome	3775400000	USD
	us-gaap	Noninterest Income NoninterestIncome	3470100000	USD
CY2021Q3	ntrs	Security Commissionsand Trading Income SecurityCommissionsandTradingIncome	36500000	USD
CY2021Q3	us-gaap	Other Operating Income OtherOperatingIncome	62300000	USD
	ntrs	Security Commissionsand Trading Income SecurityCommissionsandTradingIncome	104300000	USD
	us-gaap	Other Operating Income OtherOperatingIncome	171600000	USD
CY2020Q3	ntrs	Security Commissionsand Trading Income SecurityCommissionsandTradingIncome	26000000	USD
CY2020Q3	us-gaap	Other Operating Income OtherOperatingIncome	53500000	USD
	ntrs	Security Commissionsand Trading Income SecurityCommissionsandTradingIncome	100900000	USD
	us-gaap	Other Operating Income OtherOperatingIncome	144400000	USD
CY2021Q3	us-gaap	Contract With Customer Asset Net ContractWithCustomerAssetNet	1085400000	USD
CY2020Q4	us-gaap	Contract With Customer Asset Net ContractWithCustomerAssetNet	935800000	USD
CY2021Q3	us-gaap	Interest And Fee Income Loans And Leases InterestAndFeeIncomeLoansAndLeases	181200000	USD
CY2020Q3	us-gaap	Interest And Fee Income Loans And Leases InterestAndFeeIncomeLoansAndLeases	167100000	USD
	us-gaap	Interest And Fee Income Loans And Leases InterestAndFeeIncomeLoansAndLeases	525400000	USD
	us-gaap	Interest And Fee Income Loans And Leases InterestAndFeeIncomeLoansAndLeases	606400000	USD
CY2021Q3	us-gaap	Interest Income Securities Taxable InterestIncomeSecuritiesTaxable	162900000	USD
CY2020Q3	us-gaap	Interest Income Securities Taxable InterestIncomeSecuritiesTaxable	182600000	USD
	us-gaap	Interest Income Securities Taxable InterestIncomeSecuritiesTaxable	502500000	USD
	us-gaap	Interest Income Securities Taxable InterestIncomeSecuritiesTaxable	632100000	USD
CY2021Q3	us-gaap	Interest Income Securities Tax Exempt InterestIncomeSecuritiesTaxExempt	300000	USD
CY2020Q3	us-gaap	Interest Income Securities Tax Exempt InterestIncomeSecuritiesTaxExempt	300000	USD
	us-gaap	Interest Income Securities Tax Exempt InterestIncomeSecuritiesTaxExempt	1100000	USD
	us-gaap	Interest Income Securities Tax Exempt InterestIncomeSecuritiesTaxExempt	1100000	USD
CY2021Q3	us-gaap	Interest Income Deposits With Financial Institutions InterestIncomeDepositsWithFinancialInstitutions	1900000	USD
CY2020Q3	us-gaap	Interest Income Deposits With Financial Institutions InterestIncomeDepositsWithFinancialInstitutions	2700000	USD
	us-gaap	Interest Income Deposits With Financial Institutions InterestIncomeDepositsWithFinancialInstitutions	7000000.0	USD
	us-gaap	Interest Income Deposits With Financial Institutions InterestIncomeDepositsWithFinancialInstitutions	20000000.0	USD
CY2021Q3	ntrs	Interest Income Federal Reserve Deposits And Other InterestIncomeFederalReserveDepositsAndOther	5000000.0	USD
CY2020Q3	ntrs	Interest Income Federal Reserve Deposits And Other InterestIncomeFederalReserveDepositsAndOther	2700000	USD
	ntrs	Interest Income Federal Reserve Deposits And Other InterestIncomeFederalReserveDepositsAndOther	8300000	USD
	ntrs	Interest Income Federal Reserve Deposits And Other InterestIncomeFederalReserveDepositsAndOther	31300000	USD
CY2021Q3	us-gaap	Interest And Dividend Income Operating InterestAndDividendIncomeOperating	351300000	USD
CY2020Q3	us-gaap	Interest And Dividend Income Operating InterestAndDividendIncomeOperating	355400000	USD
	us-gaap	Interest And Dividend Income Operating InterestAndDividendIncomeOperating	1044300000	USD
	us-gaap	Interest And Dividend Income Operating InterestAndDividendIncomeOperating	1290900000	USD
CY2021Q3	us-gaap	Interest Expense Deposits InterestExpenseDeposits	-16300000	USD
CY2020Q3	us-gaap	Interest Expense Deposits InterestExpenseDeposits	-3500000	USD
	us-gaap	Interest Expense Deposits InterestExpenseDeposits	-44500000	USD
	us-gaap	Interest Expense Deposits InterestExpenseDeposits	56700000	USD
CY2021Q3	us-gaap	Interest Expense Federal Funds Purchased InterestExpenseFederalFundsPurchased	0	USD
CY2020Q3	us-gaap	Interest Expense Federal Funds Purchased InterestExpenseFederalFundsPurchased	100000	USD
	us-gaap	Interest Expense Federal Funds Purchased InterestExpenseFederalFundsPurchased	-400000	USD
	us-gaap	Interest Expense Federal Funds Purchased InterestExpenseFederalFundsPurchased	2100000	USD
CY2021Q3	us-gaap	Interest Expense Securities Sold Under Agreements To Repurchase InterestExpenseSecuritiesSoldUnderAgreementsToRepurchase	100000	USD
CY2020Q3	us-gaap	Interest Expense Securities Sold Under Agreements To Repurchase InterestExpenseSecuritiesSoldUnderAgreementsToRepurchase	0	USD
	us-gaap	Interest Expense Securities Sold Under Agreements To Repurchase InterestExpenseSecuritiesSoldUnderAgreementsToRepurchase	100000	USD
	us-gaap	Interest Expense Securities Sold Under Agreements To Repurchase InterestExpenseSecuritiesSoldUnderAgreementsToRepurchase	1000000.0	USD
CY2021Q3	us-gaap	Interest Expense Other Short Term Borrowings InterestExpenseOtherShortTermBorrowings	3600000	USD
CY2020Q3	us-gaap	Interest Expense Other Short Term Borrowings InterestExpenseOtherShortTermBorrowings	5000000.0	USD
	us-gaap	Interest Expense Other Short Term Borrowings InterestExpenseOtherShortTermBorrowings	10300000	USD
	us-gaap	Interest Expense Other Short Term Borrowings InterestExpenseOtherShortTermBorrowings	40600000	USD
CY2021Q3	ntrs	Interest Expense Senior Notes InterestExpenseSeniorNotes	11700000	USD
CY2020Q3	ntrs	Interest Expense Senior Notes InterestExpenseSeniorNotes	19100000	USD
	ntrs	Interest Expense Senior Notes InterestExpenseSeniorNotes	39200000	USD
	ntrs	Interest Expense Senior Notes InterestExpenseSeniorNotes	57000000.0	USD
CY2021Q3	us-gaap	Interest Expense Other Long Term Debt InterestExpenseOtherLongTermDebt	5300000	USD
CY2020Q3	us-gaap	Interest Expense Other Long Term Debt InterestExpenseOtherLongTermDebt	5700000	USD
	us-gaap	Interest Expense Other Long Term Debt InterestExpenseOtherLongTermDebt	15900000	USD
	us-gaap	Interest Expense Other Long Term Debt InterestExpenseOtherLongTermDebt	21100000	USD
CY2021Q3	us-gaap	Interest Expense Junior Subordinated Debentures InterestExpenseJuniorSubordinatedDebentures	500000	USD
CY2020Q3	us-gaap	Interest Expense Junior Subordinated Debentures InterestExpenseJuniorSubordinatedDebentures	400000	USD
	us-gaap	Interest Expense Junior Subordinated Debentures InterestExpenseJuniorSubordinatedDebentures	1600000	USD
	us-gaap	Interest Expense Junior Subordinated Debentures InterestExpenseJuniorSubordinatedDebentures	3600000	USD
CY2021Q3	us-gaap	Interest Expense InterestExpense	4900000	USD
CY2020Q3	us-gaap	Interest Expense InterestExpense	26800000	USD
	us-gaap	Interest Expense InterestExpense	22200000	USD
	us-gaap	Interest Expense InterestExpense	182100000	USD
CY2021Q3	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	346400000	USD
CY2020Q3	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	328600000	USD
	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	1022100000	USD
	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	1108800000	USD
CY2021Q3	us-gaap	Other Operating Income OtherOperatingIncome	62300000	USD
CY2020Q3	us-gaap	Other Operating Income OtherOperatingIncome	53500000	USD
	us-gaap	Other Operating Income OtherOperatingIncome	171600000	USD
	us-gaap	Other Operating Income OtherOperatingIncome	144400000	USD
CY2021Q3	us-gaap	Marketing And Advertising Expense MarketingAndAdvertisingExpense	27200000	USD
CY2020Q3	us-gaap	Marketing And Advertising Expense MarketingAndAdvertisingExpense	23400000	USD
	us-gaap	Marketing And Advertising Expense MarketingAndAdvertisingExpense	44000000.0	USD
	us-gaap	Marketing And Advertising Expense MarketingAndAdvertisingExpense	50100000	USD
CY2021Q3	us-gaap	Other Labor Related Expenses OtherLaborRelatedExpenses	10300000	USD
CY2020Q3	us-gaap	Other Labor Related Expenses OtherLaborRelatedExpenses	11800000	USD
	us-gaap	Other Labor Related Expenses OtherLaborRelatedExpenses	26900000	USD
	us-gaap	Other Labor Related Expenses OtherLaborRelatedExpenses	20500000	USD
CY2021Q3	us-gaap	Federal Deposit Insurance Corporation Premium Expense FederalDepositInsuranceCorporationPremiumExpense	3500000	USD
CY2020Q3	us-gaap	Federal Deposit Insurance Corporation Premium Expense FederalDepositInsuranceCorporationPremiumExpense	3200000	USD
	us-gaap	Federal Deposit Insurance Corporation Premium Expense FederalDepositInsuranceCorporationPremiumExpense	11200000	USD
	us-gaap	Federal Deposit Insurance Corporation Premium Expense FederalDepositInsuranceCorporationPremiumExpense	8600000	USD
CY2021Q3	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	3400000	USD
CY2020Q3	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	4300000	USD
	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	11600000	USD
	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	12600000	USD
CY2021Q3	ntrs	Noninterest Expense Other NoninterestExpenseOther	36800000	USD
CY2020Q3	ntrs	Noninterest Expense Other NoninterestExpenseOther	84300000	USD
	ntrs	Noninterest Expense Other NoninterestExpenseOther	126700000	USD
	ntrs	Noninterest Expense Other NoninterestExpenseOther	182800000	USD
CY2021Q3	us-gaap	Other Noninterest Expense OtherNoninterestExpense	81200000	USD
CY2020Q3	us-gaap	Other Noninterest Expense OtherNoninterestExpense	127000000.0	USD
	us-gaap	Other Noninterest Expense OtherNoninterestExpense	220400000	USD
	us-gaap	Other Noninterest Expense OtherNoninterestExpense	274600000	USD
CY2021Q3	us-gaap	Defined Benefit Plan Benefit Obligation Payment For Settlement DefinedBenefitPlanBenefitObligationPaymentForSettlement	6900000	USD
	us-gaap	Defined Benefit Plan Benefit Obligation Payment For Settlement DefinedBenefitPlanBenefitObligationPaymentForSettlement	24500000	USD
CY2021Q3	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	16700000	USD
CY2020Q3	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	13900000	USD
	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	86100000	USD
	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	82800000	USD
CY2021Q3	us-gaap	Employee Service Share Based Compensation Tax Benefit From Compensation Expense EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense	4200000	USD
CY2020Q3	us-gaap	Employee Service Share Based Compensation Tax Benefit From Compensation Expense EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense	3500000	USD
	us-gaap	Employee Service Share Based Compensation Tax Benefit From Compensation Expense EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense	21600000	USD
	us-gaap	Employee Service Share Based Compensation Tax Benefit From Compensation Expense EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense	20600000	USD
CY2021Q3	us-gaap	Variable Interest Entity Entity Maximum Loss Exposure Amount VariableInterestEntityEntityMaximumLossExposureAmount	0	USD
CY2021Q3	us-gaap	Affordable Housing Tax Credits And Other Tax Benefits Amount AffordableHousingTaxCreditsAndOtherTaxBenefitsAmount	22000000	USD
CY2020Q3	us-gaap	Affordable Housing Tax Credits And Other Tax Benefits Amount AffordableHousingTaxCreditsAndOtherTaxBenefitsAmount	20700000	USD
	us-gaap	Affordable Housing Tax Credits And Other Tax Benefits Amount AffordableHousingTaxCreditsAndOtherTaxBenefitsAmount	68100000	USD
	us-gaap	Affordable Housing Tax Credits And Other Tax Benefits Amount AffordableHousingTaxCreditsAndOtherTaxBenefitsAmount	59400000	USD
CY2021Q3	us-gaap	Investment Company Voluntary Fee Waived InvestmentCompanyVoluntaryFeeWaived	76700000	USD
	us-gaap	Investment Company Voluntary Fee Waived InvestmentCompanyVoluntaryFeeWaived	206700000	USD
CY2020Q3	us-gaap	Investment Company Voluntary Fee Waived InvestmentCompanyVoluntaryFeeWaived	5400000	USD
	us-gaap	Investment Company Voluntary Fee Waived InvestmentCompanyVoluntaryFeeWaived	5700000	USD
CY2021Q3	us-gaap	Investment Company Financial Support To Investee Contractually Required Amount InvestmentCompanyFinancialSupportToInvesteeContractuallyRequiredAmount	0	USD
	us-gaap	Loss Contingency Disclosures LossContingencyDisclosures	Commitments and Contingent Liabilities<div style="margin-bottom:6pt;margin-top:6pt;text-align:justify"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">Off-Balance Sheet Financial Instruments, Guarantees and Other Commitments. </span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Northern Trust, in the normal course of business, enters into various types of commitments and issues letters of credit to meet the liquidity and credit enhancement needs of its clients. The contractual amounts of these instruments represent the maximum potential credit exposure should the instrument be fully drawn upon and the client default. To control the credit risk associated with entering into commitments and issuing letters of credit, Northern Trust subjects such activities to the same credit quality and monitoring controls as its lending activities. Northern Trust does not believe the total contractual amount of these instruments to be representative of its future credit exposure or funding requirements.</span></div><div style="margin-bottom:6pt;margin-top:6pt;text-align:justify"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The following table provides details of Northern Trust's off-balance sheet financial instruments as of September 30, 2021 and December 31, 2020.</span></div><div style="margin-top:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:120%">TABLE 74: SUMMARY OF OFF-BALANCE SHEET FINANCIAL INSTRUMENTS</span></div><div style="margin-top:5pt;text-align:justify"><table style="border-collapse:collapse;display:inline-table;margin-bottom:5pt;vertical-align:text-bottom;width:100.000%"><tr><td style="width:1.0%"/><td style="width:37.496%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:9.133%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:9.133%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:9.133%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:9.133%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:9.133%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:9.139%"/><td style="width:0.1%"/></tr><tr><td colspan="3" style="padding:0 1pt"/><td colspan="9" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:700;line-height:100%">SEPTEMBER 30, 2021</span></td><td colspan="9" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">DECEMBER 31, 2020</span></td></tr><tr><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">($ In Millions)</span></td><td colspan="3" style="border-top:1pt solid #000000;padding:2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:700;line-height:100%">ONE YEAR AND LESS</span></td><td colspan="3" style="border-top:1pt solid #000000;padding:2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:700;line-height:100%">OVER ONE YEAR</span></td><td colspan="3" style="border-top:1pt solid #000000;padding:2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:700;line-height:100%">TOTAL</span></td><td colspan="3" style="border-top:1pt solid #000000;padding:2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">ONE YEAR AND LESS</span></td><td colspan="3" style="border-top:1pt solid #000000;padding:2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">OVER ONE YEAR</span></td><td colspan="3" style="border-top:1pt solid #000000;padding:2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">TOTAL</span></td></tr><tr><td colspan="3" style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 1pt;text-align:left;vertical-align:bottom"><div><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%">Undrawn Commitments</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:5.2pt;font-weight:400;line-height:100%;position:relative;top:-2.8pt;vertical-align:baseline">(1)</span></div></td><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">$</span></td><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">9,152.6</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%"> </span></td><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">$</span></td><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">18,597.6</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%"> </span></td><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">$</span></td><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">27,750.2</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%"> </span></td><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%">11,260.5 </span></td><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%">17,678.0 </span></td><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%">28,938.5 </span></td><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"><div><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%">Standby Letters of Credit and Financial Guarantees</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:5.2pt;font-weight:400;line-height:100%;position:relative;top:-2.8pt;vertical-align:baseline">(2)(3)</span></div></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">1,727.4</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%"> </span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">453.8</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%"> </span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">2,181.2</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%"> </span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%">1,228.1 </span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%">763.5 </span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%">1,991.6 </span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%">Commercial Letters of Credit</span></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">73.1</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%"> </span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">—</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%"> </span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">73.1</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%"> </span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%">54.6 </span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%">— </span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%">54.6 </span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%">Custody Securities Lent with Indemnification</span></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">180,619.4</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%"> </span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">—</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%"> </span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">180,619.4</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%"> </span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%">157,478.0 </span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%">— </span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%">157,478.0 </span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 1pt;text-align:left;vertical-align:top"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%">Total Off-Balance Sheet Financial Instruments</span></td><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">$</span></td><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">191,572.5</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%"> </span></td><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">$</span></td><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">19,051.4</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%"> </span></td><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">$</span></td><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">210,623.9</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%"> </span></td><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%">170,021.2 </span></td><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%">18,441.5 </span></td><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%">188,462.7 </span></td><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr></table></div><div style="text-align:justify"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:4.55pt;font-style:italic;font-weight:400;line-height:120%;position:relative;top:-2.44pt;vertical-align:baseline">(1)</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-style:italic;font-weight:400;line-height:120%"> These amounts exclude $365.9 million and $384.7 million of commitments participated to others at September 30, 2021 and December 31, 2020, respectively.</span></div><div style="text-align:justify"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:4.55pt;font-style:italic;font-weight:400;line-height:120%;position:relative;top:-2.44pt;vertical-align:baseline">(2)</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-style:italic;font-weight:400;line-height:120%"> These amounts include $33.5 million and $24.2 million of standby letters of credit secured by cash deposits or participated to others as of September 30, 2021 and December 31, 2020, respectively.</span></div><div style="text-align:justify"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:4.55pt;font-style:italic;font-weight:400;line-height:120%;position:relative;top:-2.44pt;vertical-align:baseline">(3) </span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-style:italic;font-weight:400;line-height:120%">This amount includes a $509.0 million guarantee to the Fixed Income Clearing Corporation (FICC) under the sponsored member program, without taking into consideration the related collateral, as of September 30, 2021. As of December 31, 2020, there was no guarantee to the FICC as Northern Trust became a sponsored member during the third quarter of 2021.</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:4.55pt;font-style:italic;font-weight:400;line-height:120%;position:relative;top:-2.44pt;vertical-align:baseline"> </span></div><div style="margin-bottom:6pt;margin-top:6pt;text-align:justify"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%">Undrawn Commitments </span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">generally have fixed expiration dates or other termination clauses. Since a significant portion of the commitments are expected to expire without being drawn upon, the total commitment amount does not necessarily represent future loans or liquidity requirements.</span></div><div style="margin-bottom:6pt;margin-top:6pt;text-align:justify"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%">Standby Letters of Credit</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"> obligate Northern Trust to meet certain financial obligations of its clients, if, under the contractual terms of the agreement, the clients are unable to do so. These instruments are primarily issued to support public and private financial commitments, including commercial paper, bond financing, initial margin requirements on futures exchanges and similar transactions. Northern Trust is obligated to meet the entire financial obligation of these agreements and in certain cases is able to recover the amounts paid through recourse against collateral received or other participants. </span></div><div style="margin-bottom:6pt;margin-top:6pt;text-align:justify"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%">Financial Guarantees</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"> are issued by Northern Trust to guarantee the performance of a client to a third party under certain arrangements.</span></div><div style="margin-bottom:6pt;margin-top:6pt;text-align:justify"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%">Commercial Letters of Credit</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"> are instruments issued by Northern Trust on behalf of its clients that authorize a third party (the beneficiary) to draw drafts up to a stipulated amount under the specified terms and conditions of the agreement and other similar instruments. Commercial letters of credit are issued primarily to facilitate international trade.</span></div><div style="margin-bottom:6pt;margin-top:6pt;text-align:justify"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%">Custody Securities Lent with Indemnification</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"> involves Northern Trust lending securities owned by clients to borrowers who are reviewed and approved by the Northern Trust Capital Markets Credit Committee, as part of its securities custody activities and at the direction of its clients. In connection with these activities, Northern Trust has issued indemnifications to certain clients against certain losses that are a direct result of a borrower’s failure to return securities when due, should the value of such securities exceed the value of the collateral required to be posted. Borrowers are required to collateralize fully securities received with cash or marketable securities. As securities are loaned, collateral is maintained at a minimum of 100% of the fair value of the securities plus accrued interest. The collateral is revalued on a daily basis. The amount of securities loaned as of September 30, 2021 and December 31, 2020 subject to indemnification was $180.6 billion and $157.5 billion, respectively. Because of the credit quality of the borrowers and the requirement to fully collateralize securities borrowed, management believes that the exposure to credit loss from this activity is not significant and no liability was recorded as of September 30, 2021 or December 31, 2020, related to these indemnifications.</span></div><div style="margin-bottom:6pt;margin-top:6pt;text-align:justify"><span style="background-color:#ffffff;color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">Sponsored Member Program</span><span style="background-color:#ffffff;color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%">.</span><span style="background-color:#ffffff;color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%"> </span><span style="background-color:#ffffff;color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Effective during the third quarter of 2021, Northern Trust became an approved Government Securities Division (GSD) netting and sponsoring member in the FICC sponsored member program, through which Northern Trust submits eligible repurchase and reverse repurchase transactions in U.S. Government securities between Northern Trust and its sponsored member clients for novation and clearing. Northern Trust may sponsor clients to clear their eligible repurchase transactions with the FICC. As a sponsoring member, Northern Trust guarantees to the FICC the prompt and full payment and performance of its sponsored member clients’ respective obligations under the FICC GSD’s rules. To mitigate Northern Trust’s credit exposure under this guarantee, Northern Trust obtains a security interest in its sponsored member clients’ collateral. See Note 23 - Offsetting of Assets and Liabilities for additional information on Northern Trust’s repurchase and reverse repurchase agreements.</span></div><div style="margin-bottom:6pt;margin-top:6pt;text-align:justify"><span style="background-color:#ffffff;color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">Unsettled Repurchase and Reverse Repurchase Agreements</span><span style="background-color:#ffffff;color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%">.</span><span style="background-color:#ffffff;color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%"> </span><span style="background-color:#ffffff;color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Northern Trust enters into repurchase agreements and reverse repurchase agreements which may settle at a future date. In repurchase agreements, Northern Trust receives cash from and provides securities as collateral to a counterparty. In reverse repurchase agreements, Northern Trust advances cash to and receives securities as collateral from a counterparty. These transactions are recorded on the consolidated balance sheets on the settlement date. As of September 30, 2021, there were no unsettled repurchase agreements and $99.5 million of unsettled reverse repurchase agreements. As of December 31, 2020, there were no unsettled repurchase or reverse repurchase agreements. </span></div><div style="margin-bottom:6pt;margin-top:6pt;text-align:justify"><span style="background-color:#ffffff;color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">Clearing and Settlement Organizations</span><span style="background-color:#ffffff;color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%">.</span><span style="background-color:#ffffff;color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%"> </span><span style="background-color:#ffffff;color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The Bank is a participating member of various cash, securities and foreign exchange clearing and settlement organizations. It participates in these organizations on behalf of its clients and on its own behalf as a result of its own activities. A wide variety of cash and securities transactions are settled through these organizations, including those involving obligations of states and political subdivisions, asset-backed securities, commercial paper, dollar placements, and securities issued by the Government National Mortgage Association.</span></div><div style="margin-bottom:6pt;margin-top:6pt;text-align:justify"><span style="background-color:#ffffff;color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Certain of these industry clearing and settlement exchanges require their members to guarantee their obligations and liabilities and/or to provide liquidity support in the event other members do not honor their obligations as stipulated in each clearing organization’s membership agreement. Exposure related to these agreements varies, primarily as a result of fluctuations in the volume of transactions cleared through the organizations. At September 30, 2021 and December 31, 2020, Northern Trust has not recorded any material liabilities under these arrangements as Northern Trust believes the likelihood that a clearing or settlement exchange (of which Northern Trust is a member) would become insolvent is remote. Controls related to these clearing transactions are closely monitored by management to protect the assets of Northern Trust and its clients.</span></div><div style="margin-bottom:6pt;margin-top:6pt;text-align:justify"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">Legal Proceedings.</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"> In the normal course of business, the Corporation and its subsidiaries are routinely defendants in or parties to pending and threatened legal actions, and are subject to regulatory examinations, information-gathering requests, investigations, and proceedings, both formal and informal. In certain legal actions, claims for substantial monetary damages are </span></div><div style="margin-bottom:6pt;margin-top:6pt;text-align:justify"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">asserted. In regulatory matters, claims for disgorgement, restitution, penalties and/or other remedial actions or sanctions may be sought.</span></div><div style="margin-bottom:6pt;margin-top:6pt;text-align:justify"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Based on current knowledge, after consultation with legal counsel and after taking into account current accruals, management does not believe that losses, fines or penalties, if any, arising from pending litigation or threatened legal actions or regulatory matters either individually or in the aggregate, after giving effect to applicable reserves and insurance coverage will have a material adverse effect on the consolidated financial position or liquidity of the Corporation, although such matters could have a material adverse effect on the Corporation’s operating results for a particular period.</span></div><div style="margin-bottom:6pt;margin-top:6pt;text-align:justify"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Under GAAP, (i) an event is “probable” if the “future event or events are likely to occur”; (ii) an event is “reasonably possible” if “the chance of the future event or events occurring is more than remote but less than likely”; and (iii) an event is “remote” if “the chance of the future event or events occurring is slight.”</span></div><div style="margin-bottom:6pt;margin-top:6pt;text-align:justify"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The outcome of litigation and regulatory matters is inherently difficult to predict and/or the range of loss often cannot be reasonably estimated, particularly for matters that (i) will be decided by a jury, (ii) are in early stages, (iii) involve uncertainty as to the likelihood of a class being certified or the ultimate size of the class, (iv) are subject to appeals or motions, (v) involve significant factual issues to be resolved, including with respect to the amount of damages, (vi) do not specify the amount of damages sought or (vii) seek very large damages based on novel and complex damage and liability legal theories. Accordingly, the Corporation cannot reasonably estimate the eventual outcome of these pending matters, the timing of their ultimate resolution or what the eventual loss, fines or penalties, if any, related to each pending matter will be.</span></div><div style="margin-bottom:6pt;margin-top:6pt;text-align:justify"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">In accordance with applicable accounting guidance, the Corporation records accruals for litigation and regulatory matters when those matters present loss contingencies that are both probable and reasonably estimable. When loss contingencies are not both probable and reasonably estimable, the Corporation does not record accruals. No material accruals have been recorded for pending litigation or threatened legal actions or regulatory matters.</span></div><div style="margin-bottom:6pt;margin-top:6pt;text-align:justify"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">For a limited number of matters for which a loss is reasonably possible in future periods, whether in excess of an accrued liability or where there is no accrued liability, the Corporation is able to estimate a range of possible loss. As of September 30, 2021, the Corporation has estimated the range of reasonably possible loss for these matters to be from zero to approximately $20 million in the aggregate. The Corporation’s estimate with respect to the aggregate range of reasonably possible loss is based upon currently available information and is subject to significant judgment and a variety of assumptions and known and unknown uncertainties. The matters underlying the estimated range will change from time to time, and actual results may vary significantly from the current estimate.</span></div><div style="margin-bottom:6pt;margin-top:6pt;text-align:justify"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">In certain other pending matters, there may be a range of reasonably possible loss (including reasonably possible loss in excess of amounts accrued) that cannot be reasonably estimated for the reasons described above. Such matters are not included in the estimated range of reasonably possible loss discussed above.</span></div><div style="margin-bottom:6pt;margin-top:6pt;text-align:justify"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">In 2015, Northern Trust Fiduciary Services (Guernsey) Limited (NTFS), an indirect subsidiary of the Corporation, was charged by a French investigating magistrate judge with complicity in estate tax fraud in connection with the administration of two trusts for which it serves as trustee. Charges also were brought against a number of other persons and entities related to this matter. In 2017, a French court found no estate tax fraud had occurred and NTFS and all other persons and entities charged were acquitted. The Public Prosecutor’s Office of France appealed the court decision and in June 2018 a French appellate court issued its opinion on the matter, acquitting all persons and entities charged, including NTFS. In January 2021, the Cour de Cassation, the highest court in France, reversed the June 2018 appellate court ruling, requiring a re-trial at the appellate court level. The re-trial proceedings in the appellate court have not yet been scheduled. As trustee, NTFS provided no tax advice and had no involvement in the preparation or filing of the challenged estate tax filings.</span></div><div style="margin-bottom:6pt;margin-top:6pt;text-align:justify"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">Visa Class B Common Shares.</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"> Northern Trust, as a member of Visa U.S.A. Inc. (Visa U.S.A.) and in connection with the 2007 restructuring of Visa U.S.A. and its affiliates and the 2008 initial public offering of Visa Inc. (Visa), received certain Visa Class B common shares. The Visa Class B common shares are subject to certain selling restrictions until the final resolution of certain litigation related to interchange fees involving Visa (the covered litigation), at which time the shares are convertible into Visa Class A common shares based on a conversion rate dependent upon the ultimate cost of resolving the covered litigation. On June 28, 2018, and September 27, 2019, Visa deposited an additional $600 million and $300 million, respectively, into an escrow account previously established with respect to the covered litigation. As a result of the additional contributions to the escrow account, the rate at which Visa Class B common shares will convert into Visa Class A common shares was reduced. </span></div><div style="margin-bottom:6pt;margin-top:6pt;text-align:justify"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">In September 2018, Visa reached a proposed class settlement agreement covering damage claims but not injunctive relief claims regarding the covered litigation. In December 2019, the district court granted final approval for the proposed class settlement agreement. Certain merchants have opted out of the class settlement and are pursuing claims separately, while other merchants have appealed the approval order granted by the district court. The ultimate resolution of the covered litigation, the timing for removal of the selling restrictions on the Visa Class B common shares and the rate at which such shares will ultimately convert into Visa Class A common shares are uncertain.</span></div>In June 2016 and 2015, Northern Trust recorded a $123.1 million and $99.9 million net gain on the sale of 1.1 million and 1.0 million of its Visa Class B common shares, respectively. These sales do not affect Northern Trust’s risk related to the impact of the covered litigation on the rate at which such shares will ultimately convert into Visa Class A common shares. Northern Trust continued to hold approximately 4.1 million Visa Class B common shares, which are recorded at their original cost basis of zero, as of September 30, 2021 and December 31, 2020.
CY2021Q3	ntrs	Fair Value Disclosure Off Balance Sheet Risks Amount Current Liability FairValueDisclosureOffBalanceSheetRisksAmountCurrentLiability	191572500000	USD
CY2021Q3	ntrs	Fair Value Disclosure Off Balance Sheet Risks Amount Non Current Liability FairValueDisclosureOffBalanceSheetRisksAmountNonCurrentLiability	19051400000	USD
CY2021Q3	us-gaap	Fair Value Disclosure Offbalance Sheet Risks Amount Liability FairValueDisclosureOffbalanceSheetRisksAmountLiability	210623900000	USD
CY2020Q4	ntrs	Fair Value Disclosure Off Balance Sheet Risks Amount Current Liability FairValueDisclosureOffBalanceSheetRisksAmountCurrentLiability	170021200000	USD
CY2020Q4	ntrs	Fair Value Disclosure Off Balance Sheet Risks Amount Non Current Liability FairValueDisclosureOffBalanceSheetRisksAmountNonCurrentLiability	18441500000	USD
CY2020Q4	us-gaap	Fair Value Disclosure Offbalance Sheet Risks Amount Liability FairValueDisclosureOffbalanceSheetRisksAmountLiability	188462700000	USD
CY2020Q4	ntrs	Guarantees To Sponsored Member Programs GuaranteesToSponsoredMemberPrograms	0	USD
CY2021Q3	ntrs	Securities Lending Related Collateral Maintenance SecuritiesLendingRelatedCollateralMaintenance	1
CY2021Q3	ntrs	Securities Sold Under Agreements To Repurchase Unsettled SecuritiesSoldUnderAgreementsToRepurchaseUnsettled	0	USD
CY2021Q3	ntrs	Securities Purchased Under Agreements To Resell Unsettled SecuritiesPurchasedUnderAgreementsToResellUnsettled	99500000	USD
CY2020Q4	us-gaap	Repurchase Agreement Counterparty Amount At Risk RepurchaseAgreementCounterpartyAmountAtRisk	0	USD
CY2020Q4	us-gaap	Resell Agreements Period End Amounts Excluding Effects Of Agreements Reported Net By Counterparty ResellAgreementsPeriodEndAmountsExcludingEffectsOfAgreementsReportedNetByCounterparty	0	USD
CY2021Q3	us-gaap	Loss Contingency Accrual At Carrying Value LossContingencyAccrualAtCarryingValue	0	USD
CY2021Q3	us-gaap	Derivative Notional Amount DerivativeNotionalAmount	325230900000	USD
CY2021Q3	us-gaap	Derivative Asset Fair Value Gross Asset Including Not Subject To Master Netting Arrangement DerivativeAssetFairValueGrossAssetIncludingNotSubjectToMasterNettingArrangement	3004200000	USD
CY2021Q3	us-gaap	Derivative Liability Fair Value Gross Liability Including Not Subject To Master Netting Arrangement DerivativeLiabilityFairValueGrossLiabilityIncludingNotSubjectToMasterNettingArrangement	2756700000	USD
CY2020Q4	us-gaap	Derivative Notional Amount DerivativeNotionalAmount	346752100000	USD
CY2020Q4	us-gaap	Derivative Asset Fair Value Gross Asset Including Not Subject To Master Netting Arrangement DerivativeAssetFairValueGrossAssetIncludingNotSubjectToMasterNettingArrangement	4558200000	USD
CY2020Q4	us-gaap	Derivative Liability Fair Value Gross Liability Including Not Subject To Master Netting Arrangement DerivativeLiabilityFairValueGrossLiabilityIncludingNotSubjectToMasterNettingArrangement	4882800000	USD
CY2021Q3	us-gaap	Derivative Asset Fair Value Gross Liability DerivativeAssetFairValueGrossLiability	939500000	USD
CY2021Q3	us-gaap	Derivative Liability Fair Value Gross Asset DerivativeLiabilityFairValueGrossAsset	2333900000	USD
CY2020Q4	us-gaap	Derivative Asset Fair Value Gross Liability DerivativeAssetFairValueGrossLiability	3507800000	USD
CY2020Q4	us-gaap	Derivative Liability Fair Value Gross Asset DerivativeLiabilityFairValueGrossAsset	2817100000	USD
CY2021Q3	us-gaap	Derivative Assets DerivativeAssets	2064700000	USD
CY2021Q3	us-gaap	Derivative Liabilities DerivativeLiabilities	422800000	USD
CY2020Q4	us-gaap	Derivative Assets DerivativeAssets	1050400000	USD
CY2020Q4	us-gaap	Derivative Liabilities DerivativeLiabilities	2065700000	USD
CY2020Q3	us-gaap	Gain Loss On Discontinuation Of Cash Flow Hedge Due To Forecasted Transaction Probable Of Not Occurring Net GainLossOnDiscontinuationOfCashFlowHedgeDueToForecastedTransactionProbableOfNotOccurringNet	0	USD
CY2021Q3	us-gaap	Gain Loss On Discontinuation Of Cash Flow Hedge Due To Forecasted Transaction Probable Of Not Occurring Net GainLossOnDiscontinuationOfCashFlowHedgeDueToForecastedTransactionProbableOfNotOccurringNet	0	USD
	us-gaap	Gain Loss On Discontinuation Of Cash Flow Hedge Due To Forecasted Transaction Probable Of Not Occurring Net GainLossOnDiscontinuationOfCashFlowHedgeDueToForecastedTransactionProbableOfNotOccurringNet	0	USD
	us-gaap	Gain Loss On Discontinuation Of Cash Flow Hedge Due To Forecasted Transaction Probable Of Not Occurring Net GainLossOnDiscontinuationOfCashFlowHedgeDueToForecastedTransactionProbableOfNotOccurringNet	0	USD
	us-gaap	Maximum Length Of Time Foreign Currency Cash Flow Hedge MaximumLengthOfTimeForeignCurrencyCashFlowHedge	P23M
CY2021Q3	us-gaap	Interest And Dividend Income Operating InterestAndDividendIncomeOperating	351300000	USD
CY2020Q3	us-gaap	Interest And Dividend Income Operating InterestAndDividendIncomeOperating	355400000	USD
CY2021Q3	us-gaap	Interest Expense InterestExpense	4900000	USD
CY2020Q3	us-gaap	Interest Expense InterestExpense	26800000	USD
CY2021Q3	us-gaap	Noninterest Income Other Operating Income NoninterestIncomeOtherOperatingIncome	62300000	USD
CY2020Q3	us-gaap	Noninterest Income Other Operating Income NoninterestIncomeOtherOperatingIncome	53500000	USD
	us-gaap	Interest And Dividend Income Operating InterestAndDividendIncomeOperating	1044300000	USD
	us-gaap	Interest And Dividend Income Operating InterestAndDividendIncomeOperating	1290900000	USD
	us-gaap	Interest Expense InterestExpense	22200000	USD
	us-gaap	Interest Expense InterestExpense	182100000	USD
	us-gaap	Noninterest Income Other Operating Income NoninterestIncomeOtherOperatingIncome	171600000	USD
	us-gaap	Noninterest Income Other Operating Income NoninterestIncomeOtherOperatingIncome	144400000	USD
CY2021Q3	us-gaap	Hedged Asset Fair Value Hedge HedgedAssetFairValueHedge	1788700000	USD
CY2021Q3	us-gaap	Hedged Asset Fair Value Hedge Cumulative Increase Decrease HedgedAssetFairValueHedgeCumulativeIncreaseDecrease	26900000	USD
CY2020Q4	us-gaap	Hedged Asset Fair Value Hedge HedgedAssetFairValueHedge	2075100000	USD
CY2020Q4	us-gaap	Hedged Asset Fair Value Hedge Cumulative Increase Decrease HedgedAssetFairValueHedgeCumulativeIncreaseDecrease	48800000	USD
CY2021Q3	us-gaap	Hedged Liability Fair Value Hedge HedgedLiabilityFairValueHedge	2745500000	USD
CY2021Q3	us-gaap	Hedged Liability Fair Value Hedge Cumulative Increase Decrease HedgedLiabilityFairValueHedgeCumulativeIncreaseDecrease	96900000	USD
CY2020Q4	us-gaap	Hedged Liability Fair Value Hedge HedgedLiabilityFairValueHedge	2745100000	USD
CY2020Q4	us-gaap	Hedged Liability Fair Value Hedge Cumulative Increase Decrease HedgedLiabilityFairValueHedgeCumulativeIncreaseDecrease	221500000	USD
CY2021Q3	us-gaap	Fair Value Hedges At Fair Value Net FairValueHedgesAtFairValueNet	4534200000	USD
CY2021Q3	ntrs	Hedged Asset Liability Fair Value Hedge Cumulative Increase Decrease Net HedgedAssetLiabilityFairValueHedgeCumulativeIncreaseDecreaseNet	123800000	USD
CY2020Q4	us-gaap	Fair Value Hedges At Fair Value Net FairValueHedgesAtFairValueNet	4820200000	USD
CY2020Q4	ntrs	Hedged Asset Liability Fair Value Hedge Cumulative Increase Decrease Net HedgedAssetLiabilityFairValueHedgeCumulativeIncreaseDecreaseNet	270300000	USD
CY2021Q3	ntrs	Hedged Asset Fair Value Hedge Discontinued Cumulative Increase Decrease HedgedAssetFairValueHedgeDiscontinuedCumulativeIncreaseDecrease	9800000	USD
CY2021Q3	ntrs	Hedged Liability Fair Value Hedge Discontinued Cumulative Increase Decrease HedgedLiabilityFairValueHedgeDiscontinuedCumulativeIncreaseDecrease	0	USD
CY2020Q4	ntrs	Hedged Asset Fair Value Hedge Discontinued Cumulative Increase Decrease HedgedAssetFairValueHedgeDiscontinuedCumulativeIncreaseDecrease	10400000	USD
CY2020Q4	ntrs	Hedged Liability Fair Value Hedge Discontinued Cumulative Increase Decrease HedgedLiabilityFairValueHedgeDiscontinuedCumulativeIncreaseDecrease	0	USD
CY2021Q3	ntrs	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Before Reclassification After Ta OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAfterTa	86700000	USD
CY2020Q3	ntrs	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Before Reclassification After Ta OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAfterTa	-117400000	USD
	ntrs	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Before Reclassification After Ta OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAfterTa	157300000	USD
	ntrs	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Before Reclassification After Ta OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAfterTa	-29800000	USD
CY2021Q3	us-gaap	Derivative Fair Value Of Derivative Asset DerivativeFairValueOfDerivativeAsset	2152500000	USD
CY2021Q3	us-gaap	Derivative Asset Fair Value Gross Liability DerivativeAssetFairValueGrossLiability	939500000	USD
CY2021Q3	us-gaap	Derivative Fair Value Of Derivative Asset Amount Not Offset Against Collateral DerivativeFairValueOfDerivativeAssetAmountNotOffsetAgainstCollateral	1213000000	USD
CY2021Q3	us-gaap	Derivative Collateral Obligation To Return Cash DerivativeCollateralObligationToReturnCash	2800000	USD
CY2021Q3	us-gaap	Derivative Fair Value Of Derivative Asset Amount Offset Against Collateral DerivativeFairValueOfDerivativeAssetAmountOffsetAgainstCollateral	1210200000	USD
CY2021Q3	us-gaap	Derivative Asset Not Subject To Master Netting Arrangement DerivativeAssetNotSubjectToMasterNettingArrangement	851700000	USD
CY2021Q3	us-gaap	Derivative Asset Not Subject To Master Netting Arrangement DerivativeAssetNotSubjectToMasterNettingArrangement	851700000	USD
CY2021Q3	us-gaap	Derivative Asset Not Subject To Master Netting Arrangement Deduction DerivativeAssetNotSubjectToMasterNettingArrangementDeduction	0	USD
CY2021Q3	ntrs	Derivative Asset Not Subjectto Master Netting Arrangement Net DerivativeAssetNotSubjecttoMasterNettingArrangementNet	851700000	USD
CY2021Q3	us-gaap	Derivative Asset Fair Value Gross Asset Including Not Subject To Master Netting Arrangement DerivativeAssetFairValueGrossAssetIncludingNotSubjectToMasterNettingArrangement	3004200000	USD
CY2021Q3	us-gaap	Derivative Asset Fair Value Gross Liability DerivativeAssetFairValueGrossLiability	939500000	USD
CY2021Q3	us-gaap	Derivative Assets DerivativeAssets	2064700000	USD
CY2021Q3	ntrs	Derivative Asset Not Offset DerivativeAssetNotOffset	2800000	USD
CY2021Q3	us-gaap	Derivative Asset Fair Value Offset Against Collateral Net Of Not Subject To Master Netting Arrangement Policy Election DerivativeAssetFairValueOffsetAgainstCollateralNetOfNotSubjectToMasterNettingArrangementPolicyElection	2061900000	USD
CY2021Q3	us-gaap	Securities Purchased Under Agreements To Resell Gross SecuritiesPurchasedUnderAgreementsToResellGross	1372800000	USD
CY2021Q3	us-gaap	Securities Purchased Under Agreements To Resell Liability SecuritiesPurchasedUnderAgreementsToResellLiability	500000000.0	USD
CY2021Q3	us-gaap	Securities Purchased Under Agreements To Resell SecuritiesPurchasedUnderAgreementsToResell	872800000	USD
CY2021Q3	ntrs	Derivative Asset Securities Purchased Under Agreements To Resell Collateral DerivativeAssetSecuritiesPurchasedUnderAgreementsToResellCollateral	872800000	USD
CY2020Q4	us-gaap	Derivative Fair Value Of Derivative Asset DerivativeFairValueOfDerivativeAsset	4097200000	USD
CY2020Q4	us-gaap	Derivative Asset Fair Value Gross Liability DerivativeAssetFairValueGrossLiability	3507800000	USD
CY2020Q4	us-gaap	Derivative Fair Value Of Derivative Asset Amount Not Offset Against Collateral DerivativeFairValueOfDerivativeAssetAmountNotOffsetAgainstCollateral	589400000	USD
CY2020Q4	us-gaap	Derivative Collateral Obligation To Return Cash DerivativeCollateralObligationToReturnCash	900000	USD
CY2020Q4	us-gaap	Derivative Fair Value Of Derivative Asset Amount Offset Against Collateral DerivativeFairValueOfDerivativeAssetAmountOffsetAgainstCollateral	588500000	USD
CY2020Q4	us-gaap	Derivative Asset Not Subject To Master Netting Arrangement DerivativeAssetNotSubjectToMasterNettingArrangement	461000000.0	USD
CY2020Q4	us-gaap	Derivative Asset Not Subject To Master Netting Arrangement DerivativeAssetNotSubjectToMasterNettingArrangement	461000000.0	USD
CY2020Q4	us-gaap	Derivative Asset Not Subject To Master Netting Arrangement Deduction DerivativeAssetNotSubjectToMasterNettingArrangementDeduction	0	USD
CY2020Q4	ntrs	Derivative Asset Not Subjectto Master Netting Arrangement Net DerivativeAssetNotSubjecttoMasterNettingArrangementNet	461000000.0	USD
CY2020Q4	us-gaap	Derivative Asset Fair Value Gross Asset Including Not Subject To Master Netting Arrangement DerivativeAssetFairValueGrossAssetIncludingNotSubjectToMasterNettingArrangement	4558200000	USD
CY2020Q4	us-gaap	Derivative Asset Fair Value Gross Liability DerivativeAssetFairValueGrossLiability	3507800000	USD
CY2020Q4	us-gaap	Derivative Assets DerivativeAssets	1050400000	USD
CY2020Q4	ntrs	Derivative Asset Not Offset DerivativeAssetNotOffset	900000	USD
CY2020Q4	us-gaap	Derivative Asset Fair Value Offset Against Collateral Net Of Not Subject To Master Netting Arrangement Policy Election DerivativeAssetFairValueOffsetAgainstCollateralNetOfNotSubjectToMasterNettingArrangementPolicyElection	1049500000	USD
CY2020Q4	us-gaap	Securities Purchased Under Agreements To Resell Gross SecuritiesPurchasedUnderAgreementsToResellGross	1596500000	USD
CY2020Q4	us-gaap	Securities Purchased Under Agreements To Resell SecuritiesPurchasedUnderAgreementsToResell	1596500000	USD
CY2020Q4	ntrs	Derivative Asset Securities Purchased Under Agreements To Resell Collateral DerivativeAssetSecuritiesPurchasedUnderAgreementsToResellCollateral	1596500000	USD
CY2021Q3	ntrs	Other Assets Excluding Derivatives And Non Financial Instruments OtherAssetsExcludingDerivativesAndNonFinancialInstruments	7700000000	USD
CY2020Q4	ntrs	Other Assets Excluding Derivatives And Non Financial Instruments OtherAssetsExcludingDerivativesAndNonFinancialInstruments	7300000000	USD
CY2021Q3	us-gaap	Derivative Fair Value Of Derivative Liability DerivativeFairValueOfDerivativeLiability	2509100000	USD
CY2021Q3	us-gaap	Derivative Liability Fair Value Gross Asset DerivativeLiabilityFairValueGrossAsset	2333900000	USD
CY2021Q3	us-gaap	Derivative Fair Value Of Derivative Liability Amount Not Offset Against Collateral DerivativeFairValueOfDerivativeLiabilityAmountNotOffsetAgainstCollateral	175200000	USD
CY2021Q3	us-gaap	Derivative Collateral Right To Reclaim Cash DerivativeCollateralRightToReclaimCash	500000	USD
CY2021Q3	us-gaap	Derivative Fair Value Of Derivative Liability Amount Offset Against Collateral DerivativeFairValueOfDerivativeLiabilityAmountOffsetAgainstCollateral	174700000	USD
CY2021Q3	us-gaap	Derivative Liability Not Subject To Master Netting Arrangement DerivativeLiabilityNotSubjectToMasterNettingArrangement	247600000	USD
CY2021Q3	us-gaap	Derivative Liability Not Subject To Master Netting Arrangement DerivativeLiabilityNotSubjectToMasterNettingArrangement	247600000	USD
CY2021Q3	us-gaap	Derivative Liability Not Subject To Master Netting Arrangement Deduction DerivativeLiabilityNotSubjectToMasterNettingArrangementDeduction	0	USD
CY2021Q3	ntrs	Derivative Liability Not Subject To Master Netting Arrangement Net DerivativeLiabilityNotSubjectToMasterNettingArrangementNet	247600000	USD
CY2021Q3	us-gaap	Derivative Liability Fair Value Gross Liability Including Not Subject To Master Netting Arrangement DerivativeLiabilityFairValueGrossLiabilityIncludingNotSubjectToMasterNettingArrangement	2756700000	USD
CY2021Q3	us-gaap	Derivative Liability Fair Value Gross Asset DerivativeLiabilityFairValueGrossAsset	2333900000	USD
CY2021Q3	us-gaap	Derivative Liabilities DerivativeLiabilities	422800000	USD
CY2021Q3	ntrs	Derivative Liability Not Offset DerivativeLiabilityNotOffset	500000	USD
CY2021Q3	us-gaap	Derivative Liability Fair Value Offset Against Collateral Net Of Not Subject To Master Netting Arrangement Policy Election DerivativeLiabilityFairValueOffsetAgainstCollateralNetOfNotSubjectToMasterNettingArrangementPolicyElection	422300000	USD
CY2021Q3	us-gaap	Securities Sold Under Agreements To Repurchase Gross SecuritiesSoldUnderAgreementsToRepurchaseGross	1073600000	USD
CY2021Q3	us-gaap	Securities Purchased Under Agreements To Resell Liability SecuritiesPurchasedUnderAgreementsToResellLiability	500000000.0	USD
CY2021Q3	us-gaap	Securities Sold Under Agreements To Repurchase SecuritiesSoldUnderAgreementsToRepurchase	573600000	USD
CY2021Q3	ntrs	Derivative Liability Securities Sold Under Agreement To Repurchase Collateral DerivativeLiabilitySecuritiesSoldUnderAgreementToRepurchaseCollateral	573600000	USD
CY2020Q4	us-gaap	Derivative Fair Value Of Derivative Liability DerivativeFairValueOfDerivativeLiability	3738000000	USD
CY2020Q4	us-gaap	Derivative Liability Fair Value Gross Asset DerivativeLiabilityFairValueGrossAsset	2817100000	USD
CY2020Q4	us-gaap	Derivative Fair Value Of Derivative Liability Amount Not Offset Against Collateral DerivativeFairValueOfDerivativeLiabilityAmountNotOffsetAgainstCollateral	920900000	USD
CY2020Q4	us-gaap	Derivative Collateral Right To Reclaim Cash DerivativeCollateralRightToReclaimCash	500000	USD
CY2020Q4	us-gaap	Derivative Fair Value Of Derivative Liability Amount Offset Against Collateral DerivativeFairValueOfDerivativeLiabilityAmountOffsetAgainstCollateral	920400000	USD
CY2020Q4	us-gaap	Derivative Liability Not Subject To Master Netting Arrangement DerivativeLiabilityNotSubjectToMasterNettingArrangement	1144800000	USD
CY2020Q4	us-gaap	Derivative Liability Not Subject To Master Netting Arrangement DerivativeLiabilityNotSubjectToMasterNettingArrangement	1144800000	USD
CY2020Q4	ntrs	Derivative Liability Not Subject To Master Netting Arrangement Net DerivativeLiabilityNotSubjectToMasterNettingArrangementNet	1144800000	USD
CY2020Q4	us-gaap	Derivative Liability Fair Value Gross Liability Including Not Subject To Master Netting Arrangement DerivativeLiabilityFairValueGrossLiabilityIncludingNotSubjectToMasterNettingArrangement	4882800000	USD
CY2020Q4	us-gaap	Derivative Liability Fair Value Gross Asset DerivativeLiabilityFairValueGrossAsset	2817100000	USD
CY2020Q4	us-gaap	Derivative Liabilities DerivativeLiabilities	2065700000	USD
CY2020Q4	ntrs	Derivative Liability Not Offset DerivativeLiabilityNotOffset	500000	USD
CY2020Q4	us-gaap	Derivative Liability Fair Value Offset Against Collateral Net Of Not Subject To Master Netting Arrangement Policy Election DerivativeLiabilityFairValueOffsetAgainstCollateralNetOfNotSubjectToMasterNettingArrangementPolicyElection	2065200000	USD
CY2020Q4	us-gaap	Securities Sold Under Agreements To Repurchase Gross SecuritiesSoldUnderAgreementsToRepurchaseGross	39800000	USD
CY2020Q4	us-gaap	Securities Sold Under Agreements To Repurchase SecuritiesSoldUnderAgreementsToRepurchase	39800000	USD
CY2020Q4	ntrs	Derivative Liability Securities Sold Under Agreement To Repurchase Collateral DerivativeLiabilitySecuritiesSoldUnderAgreementToRepurchaseCollateral	39800000	USD
CY2021Q3	ntrs	Other Liabilities Excluding Derivatives And Non Financial Instruments OtherLiabilitiesExcludingDerivativesAndNonFinancialInstruments	4700000000	USD
CY2020Q4	ntrs	Other Liabilities Excluding Derivatives And Non Financial Instruments OtherLiabilitiesExcludingDerivativesAndNonFinancialInstruments	3500000000	USD
CY2021Q3	us-gaap	Derivative Net Liability Position Aggregate Fair Value DerivativeNetLiabilityPositionAggregateFairValue	690400000	USD
CY2020Q4	us-gaap	Derivative Net Liability Position Aggregate Fair Value DerivativeNetLiabilityPositionAggregateFairValue	1648200000	USD
CY2021Q3	us-gaap	Collateral Already Posted Aggregate Fair Value CollateralAlreadyPostedAggregateFairValue	689000000	USD
CY2020Q4	us-gaap	Collateral Already Posted Aggregate Fair Value CollateralAlreadyPostedAggregateFairValue	1044000000	USD
CY2021Q3	us-gaap	Assets Needed For Immediate Settlement Aggregate Fair Value AssetsNeededForImmediateSettlementAggregateFairValue	1400000	USD
CY2020Q4	us-gaap	Assets Needed For Immediate Settlement Aggregate Fair Value AssetsNeededForImmediateSettlementAggregateFairValue	604200000	USD

Files In Submission

Name	View Source	Status
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$NTRS
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2021 Q3 Form 10-Q Financial Statement

#000007312421000272 Filed on October 26, 2021

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

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$NTRS NORTHERN TRUST CORP Stock $ntrs

2021 Q3 Form 10-Q Financial Statement

#000007312421000272 Filed on October 26, 2021

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$NTRS
NORTHERN TRUST CORP Stock $ntrs