$NTRS
NORTHERN TRUST CORP Stock $ntrs

$ntrs Overview Financials Valuation SEC Filings Company Website

2020 Q3 Form 10-Q Financial Statement

#000007312420000244 Filed on October 27, 2020

Income Statement

Concept	2020 Q3	2019 Q3	2019 Q2
Revenue	$355.4M	$620.8M	$640.2M
YoY Change	-42.75%	3.6%	12.77%
Cost Of Revenue	-$3.000M	$128.1M	$145.2M
YoY Change	-102.34%	2.48%	53.16%
Gross Profit	$1.485B	$1.538B	$1.507B
YoY Change	-3.43%	4.31%	0.03%
Gross Profit Margin	417.87%	247.73%	235.33%
Selling, General & Admin	$816.9M	$800.6M	$773.2M
YoY Change	2.04%	4.41%	1.12%
% of Gross Profit	55.01%	52.06%	51.32%
Research & Development
YoY Change
% of Gross Profit
Depreciation & Amortization	$123.9M	$115.3M	$112.4M
YoY Change	7.46%	1.41%	-4.18%
% of Gross Profit	8.34%	7.5%	7.46%
Operating Expenses	$1.095B	$1.029B	$999.7M
YoY Change	6.4%	4.15%	0.79%
Operating Profit	$389.9M	$508.6M	$506.9M
YoY Change	-23.34%	4.65%	-1.42%
Interest Expense	$26.80M	$203.1M	$222.8M
YoY Change	-86.8%	6.34%	44.3%
% of Operating Profit	6.87%	39.93%	43.95%
Other Income/Expense, Net
YoY Change
Pretax Income	$389.9M	$508.6M	$506.9M
YoY Change	-23.34%	5.74%	-0.06%
Income Tax	$95.40M	$124.0M	$117.5M
% Of Pretax Income	24.47%	24.38%	23.18%
Net Earnings	$294.5M	$384.6M	$389.4M
YoY Change	-23.43%	2.7%	-0.26%
Net Earnings / Revenue	82.86%	61.95%	60.82%
Basic Earnings Per Share	$1.32	$1.70	$1.76
Diluted Earnings Per Share	$1.32	$1.69	$1.75
COMMON SHARES
Basic Shares Outstanding	208.1M shares	213.2M shares	216.1M shares
Diluted Shares Outstanding	208.7M shares	214.2M shares	217.2M shares

Balance Sheet

Concept	2020 Q3	2019 Q3	2019 Q2
SHORT-TERM ASSETS
Cash & Short-Term Investments	$64.04B	$55.45B	$53.57B
YoY Change	15.5%	-0.37%	995.9%
Cash & Equivalents	$4.738B	$5.038B	$5.348B
Short-Term Investments	$59.31B	$50.41B	$48.22B
Other Short-Term Assets
YoY Change
Inventory
Prepaid Expenses
Receivables
Other Receivables
Total Short-Term Assets	$4.738B	$5.038B	$5.348B
YoY Change	-5.95%	-0.69%	9.41%
LONG-TERM ASSETS
Property, Plant & Equipment	$510.0M	$400.5M	$407.5M
YoY Change	27.34%	-4.0%	-4.97%
Goodwill	$698.0M	$687.2M	$682.0M
YoY Change	1.57%	2.16%	1.26%
Intangibles
YoY Change
Long-Term Investments	$102.8B	$77.41B	$80.63B
YoY Change	32.85%	-11.72%	-8.81%
Other Assets
YoY Change
Total Long-Term Assets	$147.3B	$119.3B	$121.2B
YoY Change	23.49%	-6.27%	-6.92%
TOTAL ASSETS
Total Short-Term Assets	$4.738B	$5.038B	$5.348B
Total Long-Term Assets	$147.3B	$119.3B	$121.2B
Total Assets	$152.1B	$124.4B	$126.6B
YoY Change	22.3%	-6.06%	-6.33%
SHORT-TERM LIABILITIES
YoY Change
Accounts Payable
YoY Change
Accrued Expenses		$552.0M	$492.0M
YoY Change
Deferred Revenue
YoY Change
Short-Term Debt	$125.1B	$97.73B	$100.7B
YoY Change	27.97%	-9.09%	-9.03%
Long-Term Debt Due	$5.772B	$7.800B	$7.766B
YoY Change	-26.0%	0.97%	1.72%
Total Short-Term Liabilities	$130.8B	$106.1B	$109.0B
YoY Change	23.33%	-7.94%	-7.93%
LONG-TERM LIABILITIES
Long-Term Debt	$5.129B	$4.035B	$3.991B
YoY Change	27.11%	19.73%	25.27%
Other Long-Term Liabilities	$4.539B	$3.427B	$2.773B
YoY Change	32.45%	0.32%	-13.34%
Total Long-Term Liabilities	$9.668B	$7.462B	$6.764B
YoY Change	29.56%	9.96%	5.92%
TOTAL LIABILITIES
Total Short-Term Liabilities	$130.8B	$106.1B	$109.0B
Total Long-Term Liabilities	$9.668B	$7.462B	$6.764B
Total Liabilities	$140.5B	$113.5B	$115.7B
YoY Change	23.74%	-6.94%	-7.22%
SHAREHOLDERS EQUITY
Retained Earnings	$12.12B	$11.44B	$11.23B
YoY Change	5.92%	9.0%	9.38%
Common Stock	$408.6M	$408.6M	$408.6M
YoY Change	0.0%	0.0%	0.0%
Preferred Stock
YoY Change
Treasury Stock (at cost)	$3.219B	$2.839B	$2.565B
YoY Change	13.38%	45.54%	47.59%
Treasury Stock Shares	37.05M shares	33.29M shares	30.28M shares
Shareholders Equity	$11.58B	$10.81B	$10.81B
YoY Change
Total Liabilities & Shareholders Equity	$152.1B	$124.4B	$126.6B
YoY Change	22.3%	-6.06%	-6.33%

Cashflow Statement

Concept	2020 Q3	2019 Q3	2019 Q2
OPERATING ACTIVITIES
Net Income	$294.5M	$384.6M	$389.4M
YoY Change	-23.43%	2.7%	-0.26%
Depreciation, Depletion And Amortization	$123.9M	$115.3M	$112.4M
YoY Change	7.46%	1.41%	-4.18%
Cash From Operating Activities	-$77.90M	$577.1M	$84.80M
YoY Change	-113.5%	-60.31%	-74.48%
INVESTING ACTIVITIES
Capital Expenditures	-$125.7M	-$118.0M	-$145.5M
YoY Change	6.53%	-9.65%	30.26%
Acquisitions
YoY Change
Other Investing Activities	$1.303B	$1.785B	-$4.131B
YoY Change	-27.03%	-4.09%	-44.38%
Cash From Investing Activities	$1.177B	$1.667B	-$4.276B
YoY Change	-29.41%	-3.67%	-43.28%
FINANCING ACTIVITIES
Cash Dividend Paid
YoY Change
Common Stock Issuance & Retirement, Net
YoY Change
Debt Paid & Issued, Net
YoY Change
Cash From Financing Activities	-838.3M	-2.484B	4.431B
YoY Change	-66.25%	-15.52%	-28.66%
NET CHANGE
Cash From Operating Activities	-77.90M	577.1M	84.80M
Cash From Investing Activities	1.177B	1.667B	-4.276B
Cash From Financing Activities	-838.3M	-2.484B	4.431B
Net Change In Cash	260.6M	-239.3M	239.5M
YoY Change	-208.9%	-197.67%	-124.06%
FREE CASH FLOW
Cash From Operating Activities	-$77.90M	$577.1M	$84.80M
Capital Expenditures	-$125.7M	-$118.0M	-$145.5M
Free Cash Flow	$47.80M	$695.1M	$230.3M
YoY Change	-93.12%	-56.13%	-48.13%

Facts In Submission

Frame	Concept Type	Concept / XBRL Key	Value	Unit
	dei	Amendment Flag AmendmentFlag	false
	dei	Document Fiscal Year Focus DocumentFiscalYearFocus	2020
	dei	Document Fiscal Period Focus DocumentFiscalPeriodFocus	Q3
	dei	Entity Central Index Key EntityCentralIndexKey	0000073124
	dei	Current Fiscal Year End Date CurrentFiscalYearEndDate	--12-31
CY2020Q3	us-gaap	Common Stock Par Or Stated Value Per Share CommonStockParOrStatedValuePerShare	1.6667
CY2019Q4	us-gaap	Common Stock Par Or Stated Value Per Share CommonStockParOrStatedValuePerShare	1.6667
CY2020Q1	us-gaap	Accounting Standards Update Extensible List AccountingStandardsUpdateExtensibleList	us-gaap:AccountingStandardsUpdate201613Member
CY2020Q1	us-gaap	Accounting Standards Update Extensible List AccountingStandardsUpdateExtensibleList	us-gaap:AccountingStandardsUpdate201613Member
CY2020Q1	us-gaap	Accounting Standards Update Extensible List AccountingStandardsUpdateExtensibleList	us-gaap:AccountingStandardsUpdate201613Member
	dei	Document Type DocumentType	10-Q
	dei	Document Quarterly Report DocumentQuarterlyReport	true
	dei	Document Period End Date DocumentPeriodEndDate	2020-09-30
	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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CY2020Q3	us-gaap	Professional Fees ProfessionalFees	186000000.0	USD
CY2019Q3	us-gaap	Professional Fees ProfessionalFees	194000000.0	USD
	us-gaap	Professional Fees ProfessionalFees	555000000.0	USD
	us-gaap	Professional Fees ProfessionalFees	568800000	USD
CY2020Q3	ntrs	Equipment And Software Expense EquipmentAndSoftwareExpense	170700000	USD
CY2019Q3	ntrs	Equipment And Software Expense EquipmentAndSoftwareExpense	151700000	USD
	ntrs	Equipment And Software Expense EquipmentAndSoftwareExpense	497100000	USD
	ntrs	Equipment And Software Expense EquipmentAndSoftwareExpense	447200000	USD
	us-gaap	Occupancy Net OccupancyNet	162900000	USD
CY2020Q3	us-gaap	Occupancy Net OccupancyNet	51800000	USD
CY2019Q3	us-gaap	Occupancy Net OccupancyNet	53000000.0	USD
	us-gaap	Occupancy Net OccupancyNet	155500000	USD
CY2020Q3	us-gaap	Other Noninterest Expense OtherNoninterestExpense	127000000.0	USD
CY2019Q3	us-gaap	Other Noninterest Expense OtherNoninterestExpense	92000000.0	USD
	us-gaap	Other Noninterest Expense OtherNoninterestExpense	274600000	USD
	us-gaap	Other Noninterest Expense OtherNoninterestExpense	241600000	USD
CY2020Q3	us-gaap	Noninterest Expense NoninterestExpense	1094700000	USD
CY2019Q3	us-gaap	Noninterest Expense NoninterestExpense	1036300000	USD
	us-gaap	Noninterest Expense NoninterestExpense	3197200000	USD
	us-gaap	Noninterest Expense NoninterestExpense	3071200000	USD
CY2020Q3	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	389900000	USD
CY2019Q3	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	508600000	USD
	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	1254200000	USD
	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	1467700000	USD
CY2020Q3	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	95400000	USD
CY2019Q3	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	124000000.0	USD
	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	285800000	USD
	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	346600000	USD
CY2020Q3	us-gaap	Net Income Loss NetIncomeLoss	294500000	USD
CY2019Q3	us-gaap	Net Income Loss NetIncomeLoss	384600000	USD
	us-gaap	Net Income Loss NetIncomeLoss	968400000	USD
	us-gaap	Net Income Loss NetIncomeLoss	1121100000	USD
CY2020Q3	us-gaap	Preferred Stock Dividends Income Statement Impact PreferredStockDividendsIncomeStatementImpact	16200000	USD
CY2019Q3	us-gaap	Preferred Stock Dividends Income Statement Impact PreferredStockDividendsIncomeStatementImpact	17400000	USD
	us-gaap	Preferred Stock Dividends Income Statement Impact PreferredStockDividendsIncomeStatementImpact	51500000	USD
	us-gaap	Preferred Stock Dividends Income Statement Impact PreferredStockDividendsIncomeStatementImpact	40600000	USD
CY2020Q3	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	278300000	USD
CY2019Q3	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	367200000	USD
	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	916900000	USD
	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	1080500000	USD
CY2020Q3	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.32
CY2019Q3	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.70
	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	4.35
	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	4.95
CY2020Q3	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.32
CY2019Q3	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.69
	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	4.34
	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	4.92
CY2020Q3	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	208106190	shares
CY2019Q3	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	213176809	shares
	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	208351088	shares
	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	215832347	shares
CY2020Q3	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	208688494	shares
CY2019Q3	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	214206576	shares
	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	209023331	shares
	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	216863563	shares
CY2020Q3	ntrs	Other Than Temporary Impairment Losses OtherThanTemporaryImpairmentLosses	0	USD
CY2019Q3	ntrs	Other Than Temporary Impairment Losses OtherThanTemporaryImpairmentLosses	100000	USD
	ntrs	Other Than Temporary Impairment Losses OtherThanTemporaryImpairmentLosses	0	USD
	ntrs	Other Than Temporary Impairment Losses OtherThanTemporaryImpairmentLosses	300000	USD
CY2020Q3	ntrs	Investment Security Gains Losses Net InvestmentSecurityGainsLossesNet	0	USD
CY2019Q3	ntrs	Investment Security Gains Losses Net InvestmentSecurityGainsLossesNet	-300000	USD
	ntrs	Investment Security Gains Losses Net InvestmentSecurityGainsLossesNet	100000	USD
	ntrs	Investment Security Gains Losses Net InvestmentSecurityGainsLossesNet	-600000	USD
CY2020Q3	us-gaap	Marketable Securities Gain Loss MarketableSecuritiesGainLoss	0	USD
CY2019Q3	us-gaap	Marketable Securities Gain Loss MarketableSecuritiesGainLoss	-400000	USD
	us-gaap	Marketable Securities Gain Loss MarketableSecuritiesGainLoss	100000	USD
	us-gaap	Marketable Securities Gain Loss MarketableSecuritiesGainLoss	-900000	USD
CY2020Q3	us-gaap	Net Income Loss NetIncomeLoss	294500000	USD
CY2019Q3	us-gaap	Net Income Loss NetIncomeLoss	384600000	USD
	us-gaap	Net Income Loss NetIncomeLoss	968400000	USD
	us-gaap	Net Income Loss NetIncomeLoss	1121100000	USD
CY2020Q3	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	33500000	USD
CY2019Q3	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	57000000.0	USD
	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	551300000	USD
	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	305000000.0	USD
CY2020Q3	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification And Tax Parent OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationAndTaxParent	1300000	USD
CY2019Q3	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
	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification And Tax Parent OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationAndTaxParent	-1900000	USD
CY2020Q3	us-gaap	Other Comprehensive Income Loss Foreign Currency Transaction And Translation Adjustment Net Of Tax OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax	1800000	USD
CY2019Q3	us-gaap	Other Comprehensive Income Loss Foreign Currency Transaction And Translation Adjustment Net Of Tax OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax	9900000	USD
	us-gaap	Other Comprehensive Income Loss Foreign Currency Transaction And Translation Adjustment Net Of Tax OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax	29500000	USD
	us-gaap	Other Comprehensive Income Loss Foreign Currency Transaction And Translation Adjustment Net Of Tax OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax	38800000	USD
CY2020Q3	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Adjustment Net Of Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax	-17500000	USD
CY2019Q3	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Adjustment Net Of Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax	-4300000	USD
	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Adjustment Net Of Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax	-33100000	USD
	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Adjustment Net Of Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax	-20800000	USD
CY2020Q3	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	54100000	USD
CY2019Q3	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	68800000	USD
	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	619200000	USD
	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	362700000	USD
CY2020Q3	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	348600000	USD
CY2019Q3	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	453400000	USD
	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	1587600000	USD
	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	1483800000	USD
CY2019Q4	us-gaap	Stockholders Equity StockholdersEquity	11091000000.0	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
CY2018Q4	us-gaap	Stockholders Equity StockholdersEquity	10508300000	USD
CY2019Q1	us-gaap	Net Income Loss NetIncomeLoss	347100000	USD
CY2019Q1	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	108400000	USD
CY2019Q1	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.60
CY2019Q1	us-gaap	Dividends Common Stock DividendsCommonStock	133700000	USD
CY2019Q1	us-gaap	Dividends Preferred Stock DividendsPreferredStock	17300000	USD
CY2019Q1	us-gaap	Stock Issued During Period Value Share Based Compensation StockIssuedDuringPeriodValueShareBasedCompensation	60800000	USD
CY2019Q1	us-gaap	Treasury Stock Value Acquired Cost Method TreasuryStockValueAcquiredCostMethod	257400000	USD
CY2019Q1	us-gaap	Stockholders Equity StockholdersEquity	10616200000	USD
CY2019Q2	us-gaap	Net Income Loss NetIncomeLoss	389400000	USD
CY2019Q2	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	185500000	USD
CY2019Q2	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.60
CY2019Q2	us-gaap	Dividends Common Stock DividendsCommonStock	130900000	USD
CY2019Q2	us-gaap	Dividends Preferred Stock DividendsPreferredStock	5900000	USD
CY2019Q2	us-gaap	Stock Issued During Period Value Share Based Compensation StockIssuedDuringPeriodValueShareBasedCompensation	22400000	USD
CY2019Q2	us-gaap	Treasury Stock Value Acquired Cost Method TreasuryStockValueAcquiredCostMethod	271200000	USD
CY2019Q2	us-gaap	Stockholders Equity StockholdersEquity	10805500000	USD
CY2019Q3	us-gaap	Net Income Loss NetIncomeLoss	384600000	USD
CY2019Q3	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	68800000	USD
CY2019Q3	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.70
CY2019Q3	us-gaap	Dividends Common Stock DividendsCommonStock	151500000	USD
CY2019Q3	us-gaap	Dividends Preferred Stock DividendsPreferredStock	17400000	USD
CY2019Q3	us-gaap	Stock Issued During Period Value Share Based Compensation StockIssuedDuringPeriodValueShareBasedCompensation	28500000	USD
CY2019Q3	us-gaap	Treasury Stock Value Acquired Cost Method TreasuryStockValueAcquiredCostMethod	307200000	USD
CY2019Q3	us-gaap	Stockholders Equity StockholdersEquity	10811300000	USD
	us-gaap	Net Income Loss NetIncomeLoss	968400000	USD
	us-gaap	Net Income Loss NetIncomeLoss	1121100000	USD
	us-gaap	Marketable Securities Gain Loss MarketableSecuritiesGainLoss	100000	USD
	us-gaap	Marketable Securities Gain Loss MarketableSecuritiesGainLoss	-900000	USD
	us-gaap	Accretion Amortization Of Discounts And Premiums Investments AccretionAmortizationOfDiscountsAndPremiumsInvestments	-63300000	USD
	us-gaap	Accretion Amortization Of Discounts And Premiums Investments AccretionAmortizationOfDiscountsAndPremiumsInvestments	-51700000	USD
	ntrs	Credit Loss Expense Reversal And Available For Sale Allowance For Credit Loss CreditLossExpenseReversalAndAvailableForSaleAllowanceForCreditLoss	127500000	USD
	ntrs	Credit Loss Expense Reversal And Available For Sale Allowance For Credit Loss CreditLossExpenseReversalAndAvailableForSaleAllowanceForCreditLoss	-13500000	USD
	us-gaap	Depreciation Nonproduction DepreciationNonproduction	85900000	USD
	us-gaap	Depreciation Nonproduction DepreciationNonproduction	76500000	USD
	us-gaap	Capitalized Computer Software Amortization1 CapitalizedComputerSoftwareAmortization1	274000000.0	USD
	us-gaap	Capitalized Computer Software Amortization1 CapitalizedComputerSoftwareAmortization1	252600000	USD
	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	12600000	USD
	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	12500000	USD
	us-gaap	Pension Contributions PensionContributions	10600000	USD
	us-gaap	Pension Contributions PensionContributions	3000000.0	USD
	us-gaap	Increase Decrease In Receivables IncreaseDecreaseInReceivables	-47600000	USD
	us-gaap	Increase Decrease In Receivables IncreaseDecreaseInReceivables	328600000	USD
	us-gaap	Increase Decrease In Interest Payable Net IncreaseDecreaseInInterestPayableNet	-5000000.0	USD
	us-gaap	Increase Decrease In Interest Payable Net IncreaseDecreaseInInterestPayableNet	-9200000	USD
	us-gaap	Increase Decrease In Derivative Assets IncreaseDecreaseInDerivativeAssets	937200000	USD
	us-gaap	Increase Decrease In Derivative Assets IncreaseDecreaseInDerivativeAssets	-39800000	USD
	us-gaap	Increase Decrease In Other Operating Capital Net IncreaseDecreaseInOtherOperatingCapitalNet	205900000	USD
	us-gaap	Increase Decrease In Other Operating Capital Net IncreaseDecreaseInOtherOperatingCapitalNet	245200000	USD
	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	420500000	USD
	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	955600000	USD
	us-gaap	Proceeds From Payments For Federal Funds Sold And Securities Purchased Under Agreements To Resell Net ProceedsFromPaymentsForFederalFundsSoldAndSecuritiesPurchasedUnderAgreementsToResellNet	-717900000	USD
	us-gaap	Proceeds From Payments For Federal Funds Sold And Securities Purchased Under Agreements To Resell Net ProceedsFromPaymentsForFederalFundsSoldAndSecuritiesPurchasedUnderAgreementsToResellNet	616300000	USD
	us-gaap	Proceeds From Payments For In Interest Bearing Deposits In Banks ProceedsFromPaymentsForInInterestBearingDepositsInBanks	2194900000	USD
	us-gaap	Proceeds From Payments For In Interest Bearing Deposits In Banks ProceedsFromPaymentsForInInterestBearingDepositsInBanks	198300000	USD
	ntrs	Payments For Proceeds From Federal Reserve And Foreign Central Bank Deposits PaymentsForProceedsFromFederalReserveAndForeignCentralBankDeposits	4592300000	USD
	ntrs	Payments For Proceeds From Federal Reserve And Foreign Central Bank Deposits PaymentsForProceedsFromFederalReserveAndForeignCentralBankDeposits	-7032200000	USD
	us-gaap	Payments To Acquire Held To Maturity Securities PaymentsToAcquireHeldToMaturitySecurities	28474000000.0	USD
	us-gaap	Payments To Acquire Held To Maturity Securities PaymentsToAcquireHeldToMaturitySecurities	9862000000.0	USD
	us-gaap	Proceeds From Maturities Prepayments And Calls Of Held To Maturity Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfHeldToMaturitySecurities	23901200000	USD
	us-gaap	Proceeds From Maturities Prepayments And Calls Of Held To Maturity Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfHeldToMaturitySecurities	12448200000	USD
	us-gaap	Payments To Acquire Available For Sale Securities Debt PaymentsToAcquireAvailableForSaleSecuritiesDebt	8558600000	USD
	us-gaap	Payments To Acquire Available For Sale Securities Debt PaymentsToAcquireAvailableForSaleSecuritiesDebt	8644300000	USD
	us-gaap	Proceeds From Sale And Maturity Of Available For Sale Securities ProceedsFromSaleAndMaturityOfAvailableForSaleSecurities	5761900000	USD
	us-gaap	Proceeds From Sale And Maturity Of Available For Sale Securities ProceedsFromSaleAndMaturityOfAvailableForSaleSecurities	6910000000.0	USD
	us-gaap	Payments For Proceeds From Loans And Leases PaymentsForProceedsFromLoansAndLeases	1339600000	USD
	us-gaap	Payments For Proceeds From Loans And Leases PaymentsForProceedsFromLoansAndLeases	-1636900000	USD
	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	102600000	USD
	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	49800000	USD
	us-gaap	Payments For Software PaymentsForSoftware	287500000	USD
	us-gaap	Payments For Software PaymentsForSoftware	304700000	USD
	ntrs	Net Change In Client Security Settlement Receivables NetChangeInClientSecuritySettlementReceivables	1377300000	USD
	ntrs	Net Change In Client Security Settlement Receivables NetChangeInClientSecuritySettlementReceivables	465100000	USD
	us-gaap	Payments To Acquire Interest In Subsidiaries And Affiliates PaymentsToAcquireInterestInSubsidiariesAndAffiliates	0	USD
	us-gaap	Payments To Acquire Interest In Subsidiaries And Affiliates PaymentsToAcquireInterestInSubsidiariesAndAffiliates	10500000	USD
	us-gaap	Payments To Acquire Life Insurance Policies PaymentsToAcquireLifeInsurancePolicies	0	USD
	us-gaap	Payments To Acquire Life Insurance Policies PaymentsToAcquireLifeInsurancePolicies	1000000000.0	USD
	us-gaap	Payments For Proceeds From Other Investing Activities PaymentsForProceedsFromOtherInvestingActivities	-477300000	USD
	us-gaap	Payments For Proceeds From Other Investing Activities PaymentsForProceedsFromOtherInvestingActivities	-492900000	USD
	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-13114500000	USD
	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	8998400000	USD
	us-gaap	Increase Decrease In Deposits IncreaseDecreaseInDeposits	12697800000	USD
	us-gaap	Increase Decrease In Deposits IncreaseDecreaseInDeposits	-6355500000	USD
	ntrs	Change In Federal Funds Purchased ChangeInFederalFundsPurchased	-1650800000	USD
	ntrs	Change In Federal Funds Purchased ChangeInFederalFundsPurchased	2393700000	USD
	us-gaap	Proceeds From Payments For In Securities Sold Under Agreements To Repurchase ProceedsFromPaymentsForInSecuritiesSoldUnderAgreementsToRepurchase	-219900000	USD
	us-gaap	Proceeds From Payments For In Securities Sold Under Agreements To Repurchase ProceedsFromPaymentsForInSecuritiesSoldUnderAgreementsToRepurchase	96900000	USD
	us-gaap	Proceeds From Repayments Of Short Term Debt Maturing In Three Months Or Less ProceedsFromRepaymentsOfShortTermDebtMaturingInThreeMonthsOrLess	-934000000.0	USD
	us-gaap	Proceeds From Repayments Of Short Term Debt Maturing In Three Months Or Less ProceedsFromRepaymentsOfShortTermDebtMaturingInThreeMonthsOrLess	-118700000	USD
	us-gaap	Payments For Repurchase Of Preferred Stock And Preference Stock PaymentsForRepurchaseOfPreferredStockAndPreferenceStock	400000000.0	USD
	us-gaap	Payments For Repurchase Of Preferred Stock And Preference Stock PaymentsForRepurchaseOfPreferredStockAndPreferenceStock	0	USD
	us-gaap	Proceeds From Issuance Of Senior Long Term Debt ProceedsFromIssuanceOfSeniorLongTermDebt	993200000	USD
	us-gaap	Proceeds From Issuance Of Senior Long Term Debt ProceedsFromIssuanceOfSeniorLongTermDebt	498000000.0	USD
	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	298500000	USD
	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	835800000	USD
	us-gaap	Proceeds From Stock Options Exercised ProceedsFromStockOptionsExercised	10700000	USD
	us-gaap	Proceeds From Stock Options Exercised ProceedsFromStockOptionsExercised	19900000	USD
	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	438800000	USD
	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	381000000.0	USD
	us-gaap	Payments Of Dividends Preferred Stock And Preference Stock PaymentsOfDividendsPreferredStockAndPreferenceStock	29700000	USD
	us-gaap	Payments Of Dividends Preferred Stock And Preference Stock PaymentsOfDividendsPreferredStockAndPreferenceStock	29100000	USD
	us-gaap	Proceeds From Payments For Other Financing Activities ProceedsFromPaymentsForOtherFinancingActivities	700000	USD
	us-gaap	Proceeds From Payments For Other Financing Activities ProceedsFromPaymentsForOtherFinancingActivities	100000	USD
	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	13032300000	USD
	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	-9498900000	USD
	us-gaap	Effect Of Exchange Rate On Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents EffectOfExchangeRateOnCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	-60000000.0	USD
	us-gaap	Effect Of Exchange Rate On Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents EffectOfExchangeRateOnCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	900000	USD
	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect	278300000	USD
	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect	456000000.0	USD
CY2019Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	4459200000	USD
CY2018Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	4581600000	USD
CY2020Q3	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	4737500000	USD
CY2019Q3	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	5037600000	USD
	us-gaap	Interest Paid Net InterestPaidNet	190300000	USD
	us-gaap	Interest Paid Net InterestPaidNet	675900000	USD
	us-gaap	Income Taxes Paid IncomeTaxesPaid	264500000	USD
	us-gaap	Income Taxes Paid IncomeTaxesPaid	360300000	USD
	us-gaap	Transfer To Other Real Estate TransferToOtherRealEstate	200000	USD
	us-gaap	Transfer To Other Real Estate TransferToOtherRealEstate	2600000	USD
	us-gaap	Debt Securities Held To Maturity Transfer Amount DebtSecuritiesHeldToMaturityTransferAmount	301500000	USD
	us-gaap	Debt Securities Held To Maturity Transfer Amount DebtSecuritiesHeldToMaturityTransferAmount	0	USD
	us-gaap	Description Of New Accounting Pronouncements Not Yet Adopted DescriptionOfNewAccountingPronouncementsNotYetAdopted	Recent Accounting Pronouncements<div style="text-align:justify;"><span style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;">On January 1, 2020, Northern Trust adopted Accounting Standards Update (ASU) No. 2016-13, “Financial Instruments—Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments” (ASU 2016-13). ASU 2016-13 significantly changed the way impairment of financial instruments is recognized by requiring immediate recognition of estimated credit losses expected to occur over the remaining life of financial instruments. The main provisions of ASU 2016-13 include (1) replacing the “incurred loss” approach under current GAAP with an “expected loss” model for instruments measured at amortized cost, (2) requiring entities to record an allowance for available for sale debt securities rather than reduce the carrying amount of the investments, as is required by the other-than-temporary-impairment model under legacy GAAP, and (3) a simplified accounting model for purchased credit-impaired debt securities and loans. </span></div><div style="text-align:justify;"><span><br/></span></div><div style="text-align:justify;"><span style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;">Upon adoption of <span style="-sec-ix-hidden:id3VybDovL2RvY3MudjEvZG9jOmVhMzI0YTdkNTUwNDQ1ZWFhMGQwYzU4ODk4NjY1NDdlL3NlYzplYTMyNGE3ZDU1MDQ0NWVhYTBkMGM1ODg5ODY2NTQ3ZV8xNDIvZnJhZzplNzMxZTQ2MDBkZTI0ZTAzODgyNDIzN2VhNWEyNTE4MS90ZXh0cmVnaW9uOmU3MzFlNDYwMGRlMjRlMDM4ODI0MjM3ZWE1YTI1MTgxXzY3NTE_7acdf046-ff2f-4998-8cc3-24bd601a00df">ASU 2016-13</span>, Northern Trust recorded a $13.7 million increase in the allowance for credit losses with a corresponding cumulative effect adjustment to decrease retained earnings by $10.1 million, net of income taxes, on January 1, 2020. Northern Trust did not restate comparative periods for the effects of applying ASU 2016-13. There was no significant impact to Northern Trust’s consolidated results of operations. Please refer to Note 7 — Allowance for Credit Losses for further information. </span></div><div style="text-align:justify;"><span><br/></span></div><div style="text-align:justify;"><span style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;">On January 1, 2020, Northern Trust adopted ASU No. 2017-04, “Intangibles—Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment” (ASU 2017-04). ASU 2017-04 amends the subsequent measurement of goodwill whereby Step 2 from the goodwill impairment test is eliminated. As a result, the goodwill impairment test is performed by comparing the fair value of a reporting unit to its carrying value and an impairment charge should be recognized for the amount by which the carrying amount exceeds the reporting unit’s fair value, not to exceed the total amount of goodwill allocated to that reporting unit. Upon adoption of ASU 2017-04, there was no significant impact to Northern Trust’s consolidated financial condition or results of operations. </span></div><div style="text-align:justify;"><span><br/></span></div><div style="text-align:justify;"><span style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;">On January 1, 2020, Northern Trust adopted ASU No. 2018-13, “Fair Value Measurement (Topic 820): Disclosure Framework—Changes to the Disclosure Requirements for Fair Value Measurement” (ASU 2018-13). The primary objective of ASU 2018-13 is to improve the effectiveness of disclosures in the notes to financial statements. Upon adoption of ASU 2018-13, there was no significant impact to Northern Trust’s consolidated financial condition or results of operations. </span></div><div style="text-align:justify;"><span><br/></span></div><div style="text-align:justify;"><span style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;">On January 1, 2020, Northern Trust adopted ASU No. 2018-15, “Intangibles—Goodwill and Other—Internal-Use Software (Subtopic 350-40): Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract (a consensus of the FASB Emerging Issues Task Force)” (ASU 2018-15). ASU 2018-15 aligns the requirements for capitalizing implementation costs incurred in a hosting arrangement that is a service contract with the requirements for capitalizing implementation costs incurred to develop or obtain internal-use software (and hosting arrangements that include an internal use software license). Upon adoption of ASU 2018-15, there was no significant impact to Northern Trust’s consolidated financial condition or results of operations. </span></div><div style="text-align:justify;"><span><br/></span></div><div style="text-align:justify;"><span style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;">On January 1, 2020, Northern Trust adopted ASU No. 2018-17, “Consolidation (Topic 810): Targeted Improvements to Related Party Guidance for Variable Interest Entities” (ASU 2018-17). ASU 2018-17 requires that indirect interests held through related parties in common control arrangements should be considered on a proportional basis (rather than as the equivalent of a direct interest in its entirety) for determining whether fees paid to decision makers and service providers are variable interests. Upon </span></div><div style="text-align:justify;"><span style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;">adoption of ASU 2018-17, there was no significant impact to Northern Trust’s consolidated financial condition or results of operations. </span></div><div style="text-align:justify;"><span><br/></span></div><div style="text-align:justify;"><span style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;">On April 1, 2020, Northern Trust adopted ASU No. 2020-04, “Reference Rate Reform (Topic 848): Facilitation of the Effects of Reference Rate Reform on Financial Reporting” (ASU 2020-04). The global transition toward alternative reference rates and away from referencing the London Interbank Offered Rate (LIBOR) and other interbank offered rates (Reference Rate Reform) is expected to have a significant impact on the volume of contract modifications, hedge accounting, and other transactions that reference LIBOR or another reference rate expected to be discontinued because of Reference Rate Reform. ASU 2020-04 provides temporary optional expedients and exceptions for applying GAAP to contract modifications, hedging relationships, and other transactions affected by Reference Rate Reform if certain criteria are met. The main provisions of ASU 2020-04 provide the following optional expedients: (1) simplification of the accounting evaluations under current GAAP for contract modifications, including loan, debt, lease and other contracts with potential embedded derivatives, if qualifying criteria are met (2) preservation of hedging relationships without dedesignation upon certain changes to the critical terms of an existing hedging relationship due to Reference Rate Reform and other optional hedge accounting relief provisions and (3) a one-time election to sell or transfer, or both sell and transfer, debt securities classified as held to maturity that reference a rate affected by Reference Rate Reform and are classified as held to maturity before January 1, 2020. </span></div><span style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;">The optional expedients in ASU 2020-04 for contract modifications and hedging relationships are applied prospectively, while the one-time election to sell or transfer, or both sell and transfer debt securities classified as held to maturity may be made at any time after March 12, 2020. The optional expedients and exceptions provided by ASU 2020-04 do not apply to contract modifications made and hedging relationships entered into or evaluated after December 31, 2022, except for hedging relationships existing as of December 31, 2022 for which an entity has elected certain optional expedients and which are retained through the end of the hedging relationship.</span><span style="background-color:rgb(255,255,255, 0.0);color:#ff0000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;"> </span>Upon adoption of ASU 2020-04, there was no significant impact on Northern Trust’s consolidated financial condition or results of operations. Northern Trust expects to elect the optional expedients provided in ASU 2020-04 and does not expect a significant impact on Northern Trust’s consolidated financial condition or results of operations as a result of electing such expedients.
CY2020Q3	us-gaap	Trading Securities TradingSecurities	600000	USD
CY2020Q3	us-gaap	Available For Sale Debt Securities Amortized Cost Basis AvailableForSaleDebtSecuritiesAmortizedCostBasis	41659200000	USD
CY2020Q3	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Gain Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax	926800000	USD
CY2020Q3	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Loss Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax	35000000.0	USD
CY2020Q3	us-gaap	Available For Sale Securities Debt Securities AvailableForSaleSecuritiesDebtSecurities	42551000000.0	USD
CY2019Q4	us-gaap	Available For Sale Debt Securities Amortized Cost Basis AvailableForSaleDebtSecuritiesAmortizedCostBasis	38722200000	USD
CY2019Q4	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Gain Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax	262700000	USD
CY2019Q4	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Loss Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax	108600000	USD
CY2019Q4	us-gaap	Available For Sale Securities Debt Securities AvailableForSaleSecuritiesDebtSecurities	38876300000	USD
CY2020Q3	us-gaap	Available For Sale Securities Debt Maturities Within One Year Amortized Cost AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearAmortizedCost	9976300000	USD
CY2020Q3	us-gaap	Available For Sale Securities Debt Maturities Within One Year Fair Value AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearFairValue	10076000000.0	USD
CY2020Q3	us-gaap	Available For Sale Securities Debt Maturities After One Through Five Years Amortized Cost AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsAmortizedCost	19133200000	USD
CY2020Q3	us-gaap	Available For Sale Securities Debt Maturities After One Through Five Years Fair Value AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsFairValue	19537800000	USD
CY2020Q3	us-gaap	Available For Sale Securities Debt Maturities After Five Through Ten Years Amortized Cost AvailableForSaleSecuritiesDebtMaturitiesAfterFiveThroughTenYearsAmortizedCost	9932400000	USD
CY2020Q3	us-gaap	Available For Sale Securities Debt Maturities After Five Through Ten Years Fair Value AvailableForSaleSecuritiesDebtMaturitiesAfterFiveThroughTenYearsFairValue	10258700000	USD
CY2020Q3	us-gaap	Available For Sale Securities Debt Maturities After Ten Years Amortized Cost AvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsAmortizedCost	2617300000	USD
CY2020Q3	us-gaap	Available For Sale Securities Debt Maturities After Ten Years Fair Value AvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsFairValue	2678500000	USD
CY2020Q3	us-gaap	Available For Sale Debt Securities Amortized Cost Basis AvailableForSaleDebtSecuritiesAmortizedCostBasis	41659200000	USD
CY2020Q3	us-gaap	Available For Sale Securities Debt Securities AvailableForSaleSecuritiesDebtSecurities	42551000000.0	USD
CY2020Q3	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position Less Than12 Months DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12Months	3758400000	USD
CY2020Q3	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position Less Than12 Months Accumulated Loss DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss	10800000	USD
CY2020Q3	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position12 Months Or Longer DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLonger	3943400000	USD
CY2020Q3	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position12 Months Or Longer Accumulated Loss DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss	24200000	USD
CY2020Q3	us-gaap	Debt Securities Available For Sale Unrealized Loss Position DebtSecuritiesAvailableForSaleUnrealizedLossPosition	7701800000	USD
CY2020Q3	us-gaap	Debt Securities Available For Sale Unrealized Loss Position Accumulated Loss DebtSecuritiesAvailableForSaleUnrealizedLossPositionAccumulatedLoss	35000000.0	USD
CY2019Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position Less Than12 Months DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12Months	7850300000	USD
CY2019Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position Less Than12 Months Accumulated Loss DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss	57000000.0	USD
CY2019Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position12 Months Or Longer DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLonger	10615200000	USD
CY2019Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position12 Months Or Longer Accumulated Loss DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss	51600000	USD
CY2019Q4	us-gaap	Debt Securities Available For Sale Unrealized Loss Position DebtSecuritiesAvailableForSaleUnrealizedLossPosition	18465500000	USD
CY2019Q4	us-gaap	Debt Securities Available For Sale Unrealized Loss Position Accumulated Loss DebtSecuritiesAvailableForSaleUnrealizedLossPositionAccumulatedLoss	108600000	USD
CY2020Q3	ntrs	Number Of Securities Unrealized Losses Position NumberOfSecuritiesUnrealizedLossesPosition	475	investment
CY2020Q3	ntrs	Securities Continuous Unrealized Loss Position Fair Value SecuritiesContinuousUnrealizedLossPositionFairValue	7700000000	USD
CY2020Q3	ntrs	Securities Continuous Unrealized Loss Position Aggregate Losses SecuritiesContinuousUnrealizedLossPositionAggregateLosses	35000000.0	USD
CY2020Q3	us-gaap	Held To Maturity Securities HeldToMaturitySecurities	16754000000.0	USD
CY2020Q3	us-gaap	Held To Maturity Securities Accumulated Unrecognized Holding Gain HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingGain	82900000	USD
CY2020Q3	us-gaap	Held To Maturity Securities Accumulated Unrecognized Holding Loss HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingLoss	90400000	USD
CY2020Q3	us-gaap	Held To Maturity Securities Fair Value HeldToMaturitySecuritiesFairValue	16746500000	USD
CY2019Q4	us-gaap	Held To Maturity Securities HeldToMaturitySecurities	12284500000	USD
CY2019Q4	us-gaap	Held To Maturity Securities Accumulated Unrecognized Holding Gain HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingGain	45700000	USD
CY2019Q4	us-gaap	Held To Maturity Securities Accumulated Unrecognized Holding Loss HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingLoss	80900000	USD
CY2019Q4	us-gaap	Held To Maturity Securities Fair Value HeldToMaturitySecuritiesFairValue	12249300000	USD
CY2020Q3	us-gaap	Held To Maturity Securities HeldToMaturitySecurities	16800000000	USD
CY2020Q3	us-gaap	Held To Maturity Securities Continuous Unrealized Loss Position Fair Value HeldToMaturitySecuritiesContinuousUnrealizedLossPositionFairValue	88700000	USD
CY2020Q3	us-gaap	Held To Maturity Securities Debt Maturities Within One Year Net Carrying Amount HeldToMaturitySecuritiesDebtMaturitiesWithinOneYearNetCarryingAmount	10516100000	USD
CY2020Q3	us-gaap	Held To Maturity Securities Debt Maturities Within One Year Fair Value HeldToMaturitySecuritiesDebtMaturitiesWithinOneYearFairValue	10527000000.0	USD
CY2020Q3	us-gaap	Held To Maturity Securities Debt Maturities After One Through Five Years Net Carrying Amount HeldToMaturitySecuritiesDebtMaturitiesAfterOneThroughFiveYearsNetCarryingAmount	5813700000	USD
CY2020Q3	us-gaap	Held To Maturity Securities Debt Maturities After One Through Five Years Fair Value HeldToMaturitySecuritiesDebtMaturitiesAfterOneThroughFiveYearsFairValue	5859400000	USD
CY2020Q3	us-gaap	Held To Maturity Securities Debt Maturities After Five Through Ten Years Net Carrying Amount HeldToMaturitySecuritiesDebtMaturitiesAfterFiveThroughTenYearsNetCarryingAmount	312700000	USD
CY2020Q3	us-gaap	Held To Maturity Securities Debt Maturities After Five Through Ten Years Fair Value HeldToMaturitySecuritiesDebtMaturitiesAfterFiveThroughTenYearsFairValue	304000000.0	USD
CY2020Q3	us-gaap	Held To Maturity Securities Debt Maturities After Ten Years Net Carrying Amount HeldToMaturitySecuritiesDebtMaturitiesAfterTenYearsNetCarryingAmount	111500000	USD
CY2020Q3	us-gaap	Held To Maturity Securities Debt Maturities After Ten Years Fair Value HeldToMaturitySecuritiesDebtMaturitiesAfterTenYearsFairValue	56100000	USD
CY2020Q3	us-gaap	Held To Maturity Securities HeldToMaturitySecurities	16754000000.0	USD
CY2020Q3	us-gaap	Held To Maturity Securities Fair Value HeldToMaturitySecuritiesFairValue	16746500000	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
	ntrs	Held To Maturity Securities Transferred From Available For Sale HeldToMaturitySecuritiesTransferredFromAvailableForSale	160800000	USD
CY2019Q3	ntrs	Held To Maturity Securities Transferred From Available For Sale HeldToMaturitySecuritiesTransferredFromAvailableForSale	160800000	USD
CY2020Q3	us-gaap	Held To Maturity Securities HeldToMaturitySecurities	16754000000.0	USD
CY2020Q3	ntrs	Proceedsfrom Saleof Investment Securities ProceedsfromSaleofInvestmentSecurities	0	USD
	ntrs	Proceedsfrom Saleof Investment Securities ProceedsfromSaleofInvestmentSecurities	689200000	USD
CY2019Q3	ntrs	Proceedsfrom Saleof Investment Securities ProceedsfromSaleofInvestmentSecurities	177300000	USD
	ntrs	Proceedsfrom Saleof Investment Securities ProceedsfromSaleofInvestmentSecurities	406600000	USD
CY2020Q3	us-gaap	Debt Securities Available For Sale Realized Gain DebtSecuritiesAvailableForSaleRealizedGain	0	USD
CY2019Q3	us-gaap	Debt Securities Available For Sale Realized Gain DebtSecuritiesAvailableForSaleRealizedGain	100000	USD
	us-gaap	Debt Securities Available For Sale Realized Gain DebtSecuritiesAvailableForSaleRealizedGain	3400000	USD
	us-gaap	Debt Securities Available For Sale Realized Gain DebtSecuritiesAvailableForSaleRealizedGain	1600000	USD
CY2020Q3	us-gaap	Debt Securities Available For Sale Realized Loss DebtSecuritiesAvailableForSaleRealizedLoss	0	USD
CY2019Q3	us-gaap	Debt Securities Available For Sale Realized Loss DebtSecuritiesAvailableForSaleRealizedLoss	400000	USD
	us-gaap	Debt Securities Available For Sale Realized Loss DebtSecuritiesAvailableForSaleRealizedLoss	3300000	USD
	us-gaap	Debt Securities Available For Sale Realized Loss DebtSecuritiesAvailableForSaleRealizedLoss	2200000	USD
CY2020Q3	us-gaap	Other Than Temporary Impairment Loss Debt Securities Portion Recognized In Earnings OtherThanTemporaryImpairmentLossDebtSecuritiesPortionRecognizedInEarnings	0	USD
CY2019Q3	us-gaap	Other Than Temporary Impairment Loss Debt Securities Portion Recognized In Earnings OtherThanTemporaryImpairmentLossDebtSecuritiesPortionRecognizedInEarnings	100000	USD
	us-gaap	Other Than Temporary Impairment Loss Debt Securities Portion Recognized In Earnings OtherThanTemporaryImpairmentLossDebtSecuritiesPortionRecognizedInEarnings	0	USD
	us-gaap	Other Than Temporary Impairment Loss Debt Securities Portion Recognized In Earnings OtherThanTemporaryImpairmentLossDebtSecuritiesPortionRecognizedInEarnings	300000	USD
CY2020Q3	us-gaap	Realized Investment Gains Losses RealizedInvestmentGainsLosses	0	USD
CY2019Q3	us-gaap	Realized Investment Gains Losses RealizedInvestmentGainsLosses	-400000	USD
	us-gaap	Realized Investment Gains Losses RealizedInvestmentGainsLosses	100000	USD
	us-gaap	Realized Investment Gains Losses RealizedInvestmentGainsLosses	-900000	USD
CY2020Q3	us-gaap	Notes Receivable Gross NotesReceivableGross	32766300000	USD
CY2019Q4	us-gaap	Notes Receivable Gross NotesReceivableGross	31409600000	USD
CY2020Q3	ntrs	Loans Receivable Overdraft Advances LoansReceivableOverdraftAdvances	1300000000	USD
CY2019Q4	ntrs	Loans Receivable Overdraft Advances LoansReceivableOverdraftAdvances	1100000000	USD
CY2020Q3	ntrs	Overdrawn Demand Deposit Accounts OverdrawnDemandDepositAccounts	11600000	USD
CY2019Q4	ntrs	Overdrawn Demand Deposit Accounts OverdrawnDemandDepositAccounts	90400000	USD
CY2020Q3	us-gaap	Financing Receivable Originated In Current Fiscal Year FinancingReceivableOriginatedInCurrentFiscalYear	5922400000	USD
CY2020Q3	us-gaap	Financing Receivable Originated In Fiscal Year Before Latest Fiscal Year FinancingReceivableOriginatedInFiscalYearBeforeLatestFiscalYear	4025000000.0	USD
CY2020Q3	us-gaap	Financing Receivable Originated Two Years Before Latest Fiscal Year FinancingReceivableOriginatedTwoYearsBeforeLatestFiscalYear	1447200000	USD
CY2020Q3	us-gaap	Financing Receivable Originated Three Years Before Latest Fiscal Year FinancingReceivableOriginatedThreeYearsBeforeLatestFiscalYear	1218900000	USD
CY2020Q3	us-gaap	Financing Receivable Originated Four Years Before Latest Fiscal Year FinancingReceivableOriginatedFourYearsBeforeLatestFiscalYear	1447800000	USD
CY2020Q3	us-gaap	Financing Receivable Originated Five Or More Years Before Latest Fiscal Year FinancingReceivableOriginatedFiveOrMoreYearsBeforeLatestFiscalYear	3293700000	USD
CY2020Q3	us-gaap	Financing Receivable Revolving FinancingReceivableRevolving	15041000000.0	USD
CY2020Q3	us-gaap	Financing Receivable Revolving Converted To Term Loan FinancingReceivableRevolvingConvertedToTermLoan	370300000	USD
CY2020Q3	us-gaap	Notes Receivable Gross NotesReceivableGross	32766300000	USD
CY2020Q3	us-gaap	Financing Receivable Recorded Investment Current FinancingReceivableRecordedInvestmentCurrent	32572000000.0	USD
CY2020Q3	ntrs	Financing Receivable Accrual FinancingReceivableAccrual	32668300000	USD
CY2020Q3	us-gaap	Financing Receivable Recorded Investment Nonaccrual Status FinancingReceivableRecordedInvestmentNonaccrualStatus	98000000.0	USD
CY2020Q3	us-gaap	Notes Receivable Gross NotesReceivableGross	32766300000	USD
CY2020Q3	us-gaap	Financing Receivable Nonaccrual No Allowance FinancingReceivableNonaccrualNoAllowance	70900000	USD
CY2020Q3	us-gaap	Other Real Estate And Foreclosed Assets OtherRealEstateAndForeclosedAssets	900000	USD
CY2020Q3	ntrs	Financing Receivable Nonaccrual Including Other Real Estate Owned FinancingReceivableNonaccrualIncludingOtherRealEstateOwned	98900000	USD
CY2019Q4	us-gaap	Financing Receivable Recorded Investment Current FinancingReceivableRecordedInvestmentCurrent	31230600000	USD
CY2019Q4	ntrs	Financing Receivable Accrual FinancingReceivableAccrual	31326000000.0	USD
CY2019Q4	us-gaap	Financing Receivable Recorded Investment Nonaccrual Status FinancingReceivableRecordedInvestmentNonaccrualStatus	83600000	USD
CY2019Q4	us-gaap	Notes Receivable Gross NotesReceivableGross	31409600000	USD
CY2019Q4	us-gaap	Financing Receivable Nonaccrual No Allowance FinancingReceivableNonaccrualNoAllowance	70600000	USD
CY2019Q4	us-gaap	Other Real Estate And Foreclosed Assets OtherRealEstateAndForeclosedAssets	3200000	USD
CY2019Q4	ntrs	Financing Receivable Nonaccrual Including Other Real Estate Owned FinancingReceivableNonaccrualIncludingOtherRealEstateOwned	86800000	USD
CY2020Q3	ntrs	Financing Receivable Nonaccrual Troubled Debt Restructuring FinancingReceivableNonaccrualTroubledDebtRestructuring	67500000	USD
CY2019Q4	ntrs	Financing Receivable Nonaccrual Troubled Debt Restructuring FinancingReceivableNonaccrualTroubledDebtRestructuring	54900000	USD
CY2020Q3	us-gaap	Financing Receivable Modifications Recorded Investment FinancingReceivableModificationsRecordedInvestment	33000000.0	USD
CY2019Q4	us-gaap	Financing Receivable Modifications Recorded Investment FinancingReceivableModificationsRecordedInvestment	27700000	USD
CY2020Q3	us-gaap	Loans And Leases Receivable Impaired Commitment To Lend LoansAndLeasesReceivableImpairedCommitmentToLend	11000000.0	USD
CY2019Q4	us-gaap	Loans And Leases Receivable Impaired Commitment To Lend LoansAndLeasesReceivableImpairedCommitmentToLend	8200000	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
CY2019Q3	us-gaap	Financing Receivable Modifications Number Of Contracts2 FinancingReceivableModificationsNumberOfContracts2	5	contract
CY2019Q3	us-gaap	Financing Receivable Modifications Post Modification Recorded Investment2 FinancingReceivableModificationsPostModificationRecordedInvestment2	3100000	USD
CY2019Q3	ntrs	Financing Receivable Troubled Debt Restructuring Postmodification Unpaid Principal Balance FinancingReceivableTroubledDebtRestructuringPostmodificationUnpaidPrincipalBalance	3100000	USD
	us-gaap	Financing Receivable Modifications Number Of Contracts2 FinancingReceivableModificationsNumberOfContracts2	34	contract
	us-gaap	Financing Receivable Modifications Post Modification Recorded Investment2 FinancingReceivableModificationsPostModificationRecordedInvestment2	28200000	USD
	ntrs	Financing Receivable Troubled Debt Restructuring Postmodification Unpaid Principal Balance FinancingReceivableTroubledDebtRestructuringPostmodificationUnpaidPrincipalBalance	29600000	USD
CY2018Q4	us-gaap	Financing Receivable Modifications Recorded Investment FinancingReceivableModificationsRecordedInvestment	1600000	USD
CY2019Q2	us-gaap	Financing Receivable Modifications Recorded Investment FinancingReceivableModificationsRecordedInvestment	1700000	USD
CY2020Q3	us-gaap	Other Real Estate And Foreclosed Assets OtherRealEstateAndForeclosedAssets	900000	USD
CY2020Q3	us-gaap	Mortgage Loans In Process Of Foreclosure Amount MortgageLoansInProcessOfForeclosureAmount	11700000	USD
CY2020Q2	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	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 DebtSecuritiesHeldToMaturityAllowanceForCreditLoss	6500000	USD
CY2020Q2	ntrs	Other Financial Assets Allowance For Credit Loss OtherFinancialAssetsAllowanceForCreditLoss	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 Losses FinancingReceivableAllowanceForCreditLosses	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 DebtSecuritiesHeldToMaturityAllowanceForCreditLoss	6900000	USD
CY2020Q3	ntrs	Other Financial Assets Allowance For Credit Loss OtherFinancialAssetsAllowanceForCreditLoss	700000	USD
CY2020Q3	ntrs	Allowance For Credit Loss AllowanceForCreditLoss	267900000	USD
CY2019Q4	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	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 DebtSecuritiesHeldToMaturityAllowanceForCreditLoss	0	USD
CY2019Q4	ntrs	Other Financial Assets Allowance For Credit Loss OtherFinancialAssetsAllowanceForCreditLoss	0	USD
CY2019Q4	ntrs	Allowance For Credit Loss AllowanceForCreditLoss	124400000	USD
	us-gaap	Debt Securities Held To Maturity Allowance For Credit Loss Writeoff DebtSecuritiesHeldToMaturityAllowanceForCreditLossWriteoff	0	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
	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
	ntrs	Change In Present Expense Reversal And Writeoff After Recovery ChangeInPresentExpenseReversalAndWriteoffAfterRecovery	-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 Losses FinancingReceivableAllowanceForCreditLosses	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 DebtSecuritiesHeldToMaturityAllowanceForCreditLoss	6900000	USD
CY2020Q3	ntrs	Other Financial Assets Allowance For Credit Loss OtherFinancialAssetsAllowanceForCreditLoss	700000	USD
CY2020Q3	ntrs	Allowance For Credit Loss AllowanceForCreditLoss	267900000	USD
CY2019Q2	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	110800000	USD
CY2019Q2	us-gaap	Off Balance Sheet Credit Loss Liability OffBalanceSheetCreditLossLiability	23300000	USD
CY2019Q2	ntrs	Allowance For Credit Loss AllowanceForCreditLoss	134100000	USD
CY2019Q3	us-gaap	Financing Receivable Allowance For Credit Losses Write Offs FinancingReceivableAllowanceForCreditLossesWriteOffs	1100000	USD
CY2019Q3	ntrs	Off Balance Sheet Allowance For Credit Loss Writeoff OffBalanceSheetAllowanceForCreditLossWriteoff	0	USD
CY2019Q3	ntrs	Allowance For Credit Loss Writeoff AllowanceForCreditLossWriteoff	1100000	USD
CY2019Q3	us-gaap	Financing Receivable Allowance For Credit Losses Recovery FinancingReceivableAllowanceForCreditLossesRecovery	1700000	USD
CY2019Q3	ntrs	Off Balance Sheet Credit Loss Liability Recovery OffBalanceSheetCreditLossLiabilityRecovery	0	USD
CY2019Q3	ntrs	Allowance For Credit Loss Recovery AllowanceForCreditLossRecovery	1700000	USD
CY2019Q3	us-gaap	Financing Receivable Allowance For Credit Loss Writeoff After Recovery FinancingReceivableAllowanceForCreditLossWriteoffAfterRecovery	-600000	USD
CY2019Q3	ntrs	Off Balance Sheet Credit Loss Liability Changein Present Value Expense Reversal OffBalanceSheetCreditLossLiabilityChangeinPresentValueExpenseReversal	0	USD
CY2019Q3	us-gaap	Financing Receivable Allowance For Credit Loss Writeoff After Recovery FinancingReceivableAllowanceForCreditLossWriteoffAfterRecovery	-600000	USD
CY2019Q3	us-gaap	Provision For Loan Losses Expensed ProvisionForLoanLossesExpensed	-5700000	USD
CY2019Q3	us-gaap	Off Balance Sheet Credit Loss Liability Credit Loss Expense Reversal OffBalanceSheetCreditLossLiabilityCreditLossExpenseReversal	-1300000	USD
CY2019Q3	ntrs	Credit Loss Expense Reversal CreditLossExpenseReversal	-7000000.0	USD
CY2019Q3	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	105700000	USD
CY2019Q3	us-gaap	Off Balance Sheet Credit Loss Liability OffBalanceSheetCreditLossLiability	22000000.0	USD
CY2019Q3	ntrs	Allowance For Credit Loss AllowanceForCreditLoss	127700000	USD
CY2018Q4	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	112600000	USD
CY2018Q4	us-gaap	Off Balance Sheet Credit Loss Liability OffBalanceSheetCreditLossLiability	25600000	USD
CY2018Q4	ntrs	Allowance For Credit Loss AllowanceForCreditLoss	138200000	USD
	us-gaap	Financing Receivable Allowance For Credit Losses Write Offs FinancingReceivableAllowanceForCreditLossesWriteOffs	2700000	USD
	ntrs	Off Balance Sheet Allowance For Credit Loss Writeoff OffBalanceSheetAllowanceForCreditLossWriteoff	0	USD
	ntrs	Allowance For Credit Loss Writeoff AllowanceForCreditLossWriteoff	2700000	USD
	us-gaap	Financing Receivable Allowance For Credit Losses Recovery FinancingReceivableAllowanceForCreditLossesRecovery	5700000	USD
	ntrs	Off Balance Sheet Credit Loss Liability Recovery OffBalanceSheetCreditLossLiabilityRecovery	0	USD
	ntrs	Allowance For Credit Loss Recovery AllowanceForCreditLossRecovery	5700000	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
	us-gaap	Financing Receivable Allowance For Credit Loss Writeoff After Recovery FinancingReceivableAllowanceForCreditLossWriteoffAfterRecovery	-3000000.0	USD
	ntrs	Off Balance Sheet Credit Loss Liability Changein Present Value Expense Reversal OffBalanceSheetCreditLossLiabilityChangeinPresentValueExpenseReversal	0	USD
	ntrs	Change In Present Expense Reversal And Writeoff After Recovery ChangeInPresentExpenseReversalAndWriteoffAfterRecovery	-3000000.0	USD
	us-gaap	Provision For Loan Losses Expensed ProvisionForLoanLossesExpensed	-9900000	USD
	us-gaap	Off Balance Sheet Credit Loss Liability Credit Loss Expense Reversal OffBalanceSheetCreditLossLiabilityCreditLossExpenseReversal	-3600000	USD
	ntrs	Credit Loss Expense Reversal CreditLossExpenseReversal	-13500000	USD
CY2019Q3	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	105700000	USD
CY2019Q3	us-gaap	Off Balance Sheet Credit Loss Liability OffBalanceSheetCreditLossLiability	22000000.0	USD
CY2019Q3	ntrs	Allowance For Credit Loss AllowanceForCreditLoss	127700000	USD
CY2020Q3	ntrs	Credit Loss Expense Reversal And Available For Sale Allowance For Credit Loss CreditLossExpenseReversalAndAvailableForSaleAllowanceForCreditLoss	500000	USD
CY2019Q3	ntrs	Credit Loss Expense Reversal And Available For Sale Allowance For Credit Loss CreditLossExpenseReversalAndAvailableForSaleAllowanceForCreditLoss	-7000000.0	USD
CY2020Q3	us-gaap	Financing Receivable Allowance For Credit Loss Writeoff After Recovery FinancingReceivableAllowanceForCreditLossWriteoffAfterRecovery	-400000	USD
CY2019Q3	us-gaap	Financing Receivable Allowance For Credit Loss Writeoff After Recovery FinancingReceivableAllowanceForCreditLossWriteoffAfterRecovery	-600000	USD
	ntrs	Credit Loss Expense Reversal And Available For Sale Allowance For Credit Loss CreditLossExpenseReversalAndAvailableForSaleAllowanceForCreditLoss	127500000	USD
	ntrs	Credit Loss Expense Reversal And Available For Sale Allowance For Credit Loss CreditLossExpenseReversalAndAvailableForSaleAllowanceForCreditLoss	-13500000	USD
	us-gaap	Financing Receivable Allowance For Credit Loss Writeoff After Recovery FinancingReceivableAllowanceForCreditLossWriteoffAfterRecovery	-2300000	USD
	us-gaap	Financing Receivable Allowance For Credit Loss Writeoff After Recovery FinancingReceivableAllowanceForCreditLossWriteoffAfterRecovery	-3000000.0	USD
	ntrs	Financing Receivable Credit Loss Estimate Time Period FinancingReceivableCreditLossEstimateTimePeriod	P2Y
CY2020Q3	us-gaap	Financing Receivable Accrued Interest After Allowance For Credit Loss FinancingReceivableAccruedInterestAfterAllowanceForCreditLoss	54200000	USD
CY2019Q4	us-gaap	Financing Receivable Accrued Interest After Allowance For Credit Loss FinancingReceivableAccruedInterestAfterAllowanceForCreditLoss	84500000	USD
CY2020Q3	us-gaap	Debt Securities Held To Maturity Accrued Interest After Allowance For Credit Loss DebtSecuritiesHeldToMaturityAccruedInterestAfterAllowanceForCreditLoss	71700000	USD
CY2019Q4	us-gaap	Debt Securities Held To Maturity Accrued Interest After Allowance For Credit Loss DebtSecuritiesHeldToMaturityAccruedInterestAfterAllowanceForCreditLoss	82300000	USD
CY2020Q3	us-gaap	Debt Securities Available For Sale Accrued Interest After Allowance For Credit Loss DebtSecuritiesAvailableForSaleAccruedInterestAfterAllowanceForCreditLoss	101000000.0	USD
CY2019Q4	us-gaap	Debt Securities Available For Sale Accrued Interest After Allowance For Credit Loss DebtSecuritiesAvailableForSaleAccruedInterestAfterAllowanceForCreditLoss	119000000.0	USD
CY2020Q3	ntrs	Other Financial Assets Accrued Interest After Allowance For Credit Loss OtherFinancialAssetsAccruedInterestAfterAllowanceForCreditLoss	1700000	USD
CY2019Q4	ntrs	Other Financial Assets Accrued Interest After Allowance For Credit Loss OtherFinancialAssetsAccruedInterestAfterAllowanceForCreditLoss	14700000	USD
CY2020Q3	us-gaap	Financing Receivable Accrued Interest Writeoff FinancingReceivableAccruedInterestWriteoff	1100000	USD
	us-gaap	Financing Receivable Accrued Interest Writeoff FinancingReceivableAccruedInterestWriteoff	3500000	USD
CY2019Q3	us-gaap	Loans And Leases Receivable Impaired Interest Lost On Nonaccrual Loans LoansAndLeasesReceivableImpairedInterestLostOnNonaccrualLoans	1800000	USD
	us-gaap	Loans And Leases Receivable Impaired Interest Lost On Nonaccrual Loans LoansAndLeasesReceivableImpairedInterestLostOnNonaccrualLoans	5700000	USD
CY2020Q2	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	210200000	USD
CY2020Q2	us-gaap	Off Balance Sheet Credit Loss Liability OffBalanceSheetCreditLossLiability	49000000.0	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	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 Losses FinancingReceivableAllowanceForCreditLosses	215400000	USD
CY2020Q3	us-gaap	Off Balance Sheet Credit Loss Liability OffBalanceSheetCreditLossLiability	44900000	USD
CY2019Q4	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	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 Losses FinancingReceivableAllowanceForCreditLosses	215400000	USD
CY2020Q3	us-gaap	Off Balance Sheet Credit Loss Liability OffBalanceSheetCreditLossLiability	44900000	USD
CY2019Q2	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	110800000	USD
CY2019Q2	us-gaap	Off Balance Sheet Credit Loss Liability OffBalanceSheetCreditLossLiability	23300000	USD
CY2019Q3	us-gaap	Financing Receivable Allowance For Credit Losses Write Offs FinancingReceivableAllowanceForCreditLossesWriteOffs	1100000	USD
CY2019Q3	ntrs	Off Balance Sheet Allowance For Credit Loss Writeoff OffBalanceSheetAllowanceForCreditLossWriteoff	0	USD
CY2019Q3	us-gaap	Financing Receivable Allowance For Credit Losses Recovery FinancingReceivableAllowanceForCreditLossesRecovery	1700000	USD
CY2019Q3	ntrs	Off Balance Sheet Credit Loss Liability Recovery OffBalanceSheetCreditLossLiabilityRecovery	0	USD
CY2019Q3	us-gaap	Financing Receivable Allowance For Credit Loss Writeoff After Recovery FinancingReceivableAllowanceForCreditLossWriteoffAfterRecovery	-600000	USD
CY2019Q3	ntrs	Off Balance Sheet Credit Loss Liability Changein Present Value Expense Reversal OffBalanceSheetCreditLossLiabilityChangeinPresentValueExpenseReversal	0	USD
CY2019Q3	us-gaap	Provision For Loan Losses Expensed ProvisionForLoanLossesExpensed	-5700000	USD
CY2019Q3	us-gaap	Off Balance Sheet Credit Loss Liability Credit Loss Expense Reversal OffBalanceSheetCreditLossLiabilityCreditLossExpenseReversal	-1300000	USD
CY2019Q3	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	105700000	USD
CY2019Q3	us-gaap	Off Balance Sheet Credit Loss Liability OffBalanceSheetCreditLossLiability	22000000.0	USD
CY2018Q4	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	112600000	USD
CY2018Q4	us-gaap	Off Balance Sheet Credit Loss Liability OffBalanceSheetCreditLossLiability	25600000	USD
	us-gaap	Financing Receivable Allowance For Credit Losses Write Offs FinancingReceivableAllowanceForCreditLossesWriteOffs	2700000	USD
	ntrs	Off Balance Sheet Allowance For Credit Loss Writeoff OffBalanceSheetAllowanceForCreditLossWriteoff	0	USD
	us-gaap	Financing Receivable Allowance For Credit Losses Recovery FinancingReceivableAllowanceForCreditLossesRecovery	5700000	USD
	ntrs	Off Balance Sheet Credit Loss Liability Recovery OffBalanceSheetCreditLossLiabilityRecovery	0	USD
	us-gaap	Financing Receivable Allowance For Credit Loss Writeoff After Recovery FinancingReceivableAllowanceForCreditLossWriteoffAfterRecovery	-3000000.0	USD
	ntrs	Off Balance Sheet Credit Loss Liability Changein Present Value Expense Reversal OffBalanceSheetCreditLossLiabilityChangeinPresentValueExpenseReversal	0	USD
	us-gaap	Provision For Loan Losses Expensed ProvisionForLoanLossesExpensed	-9900000	USD
	us-gaap	Off Balance Sheet Credit Loss Liability Credit Loss Expense Reversal OffBalanceSheetCreditLossLiabilityCreditLossExpenseReversal	-3600000	USD
CY2019Q3	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	105700000	USD
CY2019Q3	us-gaap	Off Balance Sheet Credit Loss Liability OffBalanceSheetCreditLossLiability	22000000.0	USD
CY2020Q3	us-gaap	Financing Receivable Individually Evaluated For Impairment FinancingReceivableIndividuallyEvaluatedForImpairment	98000000.0	USD
CY2019Q4	us-gaap	Financing Receivable Individually Evaluated For Impairment FinancingReceivableIndividuallyEvaluatedForImpairment	92200000	USD
CY2020Q3	us-gaap	Financing Receivable Collectively Evaluated For Impairment FinancingReceivableCollectivelyEvaluatedForImpairment	32668300000	USD
CY2019Q4	us-gaap	Financing Receivable Collectively Evaluated For Impairment FinancingReceivableCollectivelyEvaluatedForImpairment	31317400000	USD
CY2020Q3	us-gaap	Notes Receivable Gross NotesReceivableGross	32766300000	USD
CY2019Q4	us-gaap	Notes Receivable Gross NotesReceivableGross	31409600000	USD
CY2020Q3	us-gaap	Financing Receivable Allowance For Credit Losses Individually Evaluated For Impairment1 FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment1	6000000.0	USD
CY2019Q4	us-gaap	Financing Receivable Allowance For Credit Losses Individually Evaluated For Impairment1 FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment1	5000000.0	USD
CY2020Q3	us-gaap	Financing Receivable Allowance For Credit Losses Collectively Evaluated For Impairment FinancingReceivableAllowanceForCreditLossesCollectivelyEvaluatedForImpairment	209400000	USD
CY2019Q4	us-gaap	Financing Receivable Allowance For Credit Losses Collectively Evaluated For Impairment FinancingReceivableAllowanceForCreditLossesCollectivelyEvaluatedForImpairment	99500000	USD
CY2020Q3	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	215400000	USD
CY2019Q4	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	104500000	USD
CY2020Q3	ntrs	Off Balance Sheet Credit Loss Liability Individually Evaluated For Impairment OffBalanceSheetCreditLossLiabilityIndividuallyEvaluatedForImpairment	2200000	USD
CY2019Q4	ntrs	Off Balance Sheet Credit Loss Liability Individually Evaluated For Impairment OffBalanceSheetCreditLossLiabilityIndividuallyEvaluatedForImpairment	1900000	USD
CY2020Q3	ntrs	Off Balance Sheet Credit Loss Liability Collectively Evaluated For Impairment OffBalanceSheetCreditLossLiabilityCollectivelyEvaluatedForImpairment	42700000	USD
CY2019Q4	ntrs	Off Balance Sheet Credit Loss Liability Collectively Evaluated For Impairment OffBalanceSheetCreditLossLiabilityCollectivelyEvaluatedForImpairment	18000000.0	USD
CY2020Q3	us-gaap	Off Balance Sheet Credit Loss Liability OffBalanceSheetCreditLossLiability	44900000	USD
CY2019Q4	us-gaap	Off Balance Sheet Credit Loss Liability OffBalanceSheetCreditLossLiability	19900000	USD
CY2020Q3	ntrs	Financing Receivable Allowance For Credit Losses And Off Balance Sheet Credit Loss Liability FinancingReceivableAllowanceForCreditLossesAndOffBalanceSheetCreditLossLiability	260300000	USD
CY2019Q4	ntrs	Financing Receivable Allowance For Credit Losses And Off Balance Sheet Credit Loss Liability FinancingReceivableAllowanceForCreditLossesAndOffBalanceSheetCreditLossLiability	124400000	USD
CY2020Q2	us-gaap	Debt Securities Held To Maturity Allowance For Credit Loss DebtSecuritiesHeldToMaturityAllowanceForCreditLoss	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 DebtSecuritiesHeldToMaturityAllowanceForCreditLoss	6900000	USD
CY2019Q4	us-gaap	Debt Securities Held To Maturity Allowance For Credit Loss DebtSecuritiesHeldToMaturityAllowanceForCreditLoss	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 DebtSecuritiesHeldToMaturityAllowanceForCreditLoss	6900000	USD
CY2020Q1	us-gaap	Other Than Temporary Impairment Loss Debt Securities Portion Recognized In Earnings OtherThanTemporaryImpairmentLossDebtSecuritiesPortionRecognizedInEarnings	4400000	USD
CY2020Q3	ntrs	Other Financial Assets Allowance For Credit Loss OtherFinancialAssetsAllowanceForCreditLoss	700000	USD
CY2020Q3	us-gaap	Security Owned And Pledged As Collateral Fair Value SecurityOwnedAndPledgedAsCollateralFairValue	43400000000	USD
CY2019Q4	us-gaap	Security Owned And Pledged As Collateral Fair Value SecurityOwnedAndPledgedAsCollateralFairValue	42100000000	USD
CY2020Q3	us-gaap	Financial Instruments Owned And Pledged As Collateral Amount Eligible To Be Repledged By Counterparty FinancialInstrumentsOwnedAndPledgedAsCollateralAmountEligibleToBeRepledgedByCounterparty	268600000	USD
CY2019Q4	us-gaap	Financial Instruments Owned And Pledged As Collateral Amount Eligible To Be Repledged By Counterparty FinancialInstrumentsOwnedAndPledgedAsCollateralAmountEligibleToBeRepledgedByCounterparty	487200000	USD
CY2020Q3	us-gaap	Collateral Securities Repledged Delivered Or Used CollateralSecuritiesRepledgedDeliveredOrUsed	0	USD
CY2019Q4	us-gaap	Collateral Securities Repledged Delivered Or Used CollateralSecuritiesRepledgedDeliveredOrUsed	0	USD
CY2020Q3	us-gaap	Securities Held As Collateral At Fair Value SecuritiesHeldAsCollateralAtFairValue	1533400000	USD
CY2019Q4	us-gaap	Finite Lived Intangible Assets Accumulated Amortization FiniteLivedIntangibleAssetsAccumulatedAmortization	86600000	USD
CY2019Q4	us-gaap	Securities Held As Collateral At Fair Value SecuritiesHeldAsCollateralAtFairValue	707800000	USD
	ntrs	Average Interest Bearing Deposits In Federal Reserve Bank For Reserve Requirements AverageInterestBearingDepositsInFederalReserveBankForReserveRequirements	500000000	USD
CY2019Q3	ntrs	Average Interest Bearing Deposits In Federal Reserve Bank For Reserve Requirements AverageInterestBearingDepositsInFederalReserveBankForReserveRequirements	1600000000	USD
	ntrs	Average Interest Bearing Deposits In Federal Reserve Bank For Reserve Requirements AverageInterestBearingDepositsInFederalReserveBankForReserveRequirements	1500000000	USD
CY2019Q4	us-gaap	Goodwill Goodwill	696800000	USD
	us-gaap	Goodwill Foreign Currency Translation Gain Loss GoodwillForeignCurrencyTranslationGainLoss	1200000	USD
CY2020Q3	us-gaap	Goodwill Goodwill	698000000.0	USD
CY2020Q3	us-gaap	Finite Lived Intangible Assets Gross FiniteLivedIntangibleAssetsGross	214300000	USD
CY2019Q4	us-gaap	Finite Lived Intangible Assets Gross FiniteLivedIntangibleAssetsGross	207200000	USD
CY2020Q3	us-gaap	Finite Lived Intangible Assets Accumulated Amortization FiniteLivedIntangibleAssetsAccumulatedAmortization	101700000	USD
CY2020Q3	us-gaap	Finite Lived Intangible Assets Net FiniteLivedIntangibleAssetsNet	112600000	USD
CY2019Q4	us-gaap	Finite Lived Intangible Assets Net FiniteLivedIntangibleAssetsNet	120600000	USD
	us-gaap	Number Of Reportable Segments NumberOfReportableSegments	2	segment
CY2020Q3	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	1003800000	USD
CY2019Q3	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	975500000	USD
CY2020Q3	us-gaap	Foreign Currency Transaction Gain Loss Before Tax ForeignCurrencyTransactionGainLossBeforeTax	61600000	USD
CY2019Q3	us-gaap	Foreign Currency Transaction Gain Loss Before Tax ForeignCurrencyTransactionGainLossBeforeTax	59700000	USD
CY2020Q3	us-gaap	Noninterest Income Other NoninterestIncomeOther	91100000	USD
CY2019Q3	us-gaap	Noninterest Income Other NoninterestIncomeOther	85000000.0	USD
CY2020Q3	us-gaap	Noninterest Income NoninterestIncome	1156500000	USD
CY2019Q3	us-gaap	Noninterest Income NoninterestIncome	1120200000	USD
CY2020Q3	ntrs	Interest Revenue Expense Net Including Fully Taxable Equivalent Adjustment InterestRevenueExpenseNetIncludingFullyTaxableEquivalentAdjustment	336500000	USD
CY2019Q3	ntrs	Interest Revenue Expense Net Including Fully Taxable Equivalent Adjustment InterestRevenueExpenseNetIncludingFullyTaxableEquivalentAdjustment	425300000	USD
CY2020Q3	ntrs	Revenue Including Fully Taxable Equivalent Adjustment RevenueIncludingFullyTaxableEquivalentAdjustment	1493000000.0	USD
CY2019Q3	ntrs	Revenue Including Fully Taxable Equivalent Adjustment RevenueIncludingFullyTaxableEquivalentAdjustment	1545500000	USD
CY2020Q3	us-gaap	Noninterest Expense NoninterestExpense	1094700000	USD
CY2020Q3	ntrs	Credit Loss Expense Reversal And Available For Sale Allowance For Credit Loss CreditLossExpenseReversalAndAvailableForSaleAllowanceForCreditLoss	500000	USD
CY2019Q3	ntrs	Credit Loss Expense Reversal And Available For Sale Allowance For Credit Loss CreditLossExpenseReversalAndAvailableForSaleAllowanceForCreditLoss	-7000000.0	USD
CY2019Q3	us-gaap	Noninterest Expense NoninterestExpense	1036300000	USD
CY2020Q3	ntrs	Income Loss Before Income Taxes Including Fully Taxable Equivalent Adjustment IncomeLossBeforeIncomeTaxesIncludingFullyTaxableEquivalentAdjustment	397800000	USD
CY2019Q3	ntrs	Income Loss Before Income Taxes Including Fully Taxable Equivalent Adjustment IncomeLossBeforeIncomeTaxesIncludingFullyTaxableEquivalentAdjustment	516200000	USD
CY2020Q3	ntrs	Income Tax Expense Benefit Including Fully Taxable Equivalent Adjustment IncomeTaxExpenseBenefitIncludingFullyTaxableEquivalentAdjustment	103300000	USD
CY2019Q3	ntrs	Income Tax Expense Benefit Including Fully Taxable Equivalent Adjustment IncomeTaxExpenseBenefitIncludingFullyTaxableEquivalentAdjustment	131600000	USD
CY2020Q3	us-gaap	Net Income Loss NetIncomeLoss	294500000	USD
CY2019Q3	us-gaap	Net Income Loss NetIncomeLoss	384600000	USD
CY2020Q3	ntrs	Percentage Of Consolidated Net Income PercentageOfConsolidatedNetIncome	1
CY2019Q3	ntrs	Percentage Of Consolidated Net Income PercentageOfConsolidatedNetIncome	1
CY2020Q3	ntrs	Segment Reporting Information Consolidated Average Assets SegmentReportingInformationConsolidatedAverageAssets	140925400000	USD
CY2019Q3	ntrs	Segment Reporting Information Consolidated Average Assets SegmentReportingInformationConsolidatedAverageAssets	116352100000	USD
CY2020Q3	ntrs	Segment Reporting Information Fully Taxable Equivalent Adjustment SegmentReportingInformationFullyTaxableEquivalentAdjustment	7900000	USD
CY2019Q3	ntrs	Segment Reporting Information Fully Taxable Equivalent Adjustment SegmentReportingInformationFullyTaxableEquivalentAdjustment	7600000	USD
	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	2968900000	USD
	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	2859900000	USD
	us-gaap	Foreign Currency Transaction Gain Loss Before Tax ForeignCurrencyTransactionGainLossBeforeTax	221800000	USD
	us-gaap	Foreign Currency Transaction Gain Loss Before Tax ForeignCurrencyTransactionGainLossBeforeTax	186400000	USD
	us-gaap	Noninterest Income Other NoninterestIncomeOther	279400000	USD
	us-gaap	Noninterest Income Other NoninterestIncomeOther	222000000.0	USD
	us-gaap	Noninterest Income NoninterestIncome	3470100000	USD
	us-gaap	Noninterest Income NoninterestIncome	3268300000	USD
	ntrs	Interest Revenue Expense Net Including Fully Taxable Equivalent Adjustment InterestRevenueExpenseNetIncludingFullyTaxableEquivalentAdjustment	1132500000	USD
	ntrs	Interest Revenue Expense Net Including Fully Taxable Equivalent Adjustment InterestRevenueExpenseNetIncludingFullyTaxableEquivalentAdjustment	1280200000	USD
	ntrs	Revenue Including Fully Taxable Equivalent Adjustment RevenueIncludingFullyTaxableEquivalentAdjustment	4602600000	USD
	ntrs	Revenue Including Fully Taxable Equivalent Adjustment RevenueIncludingFullyTaxableEquivalentAdjustment	4602600000	USD
	ntrs	Revenue Including Fully Taxable Equivalent Adjustment RevenueIncludingFullyTaxableEquivalentAdjustment	4548500000	USD
	ntrs	Revenue Including Fully Taxable Equivalent Adjustment RevenueIncludingFullyTaxableEquivalentAdjustment	4548500000	USD
	ntrs	Credit Loss Expense Reversal And Available For Sale Allowance For Credit Loss CreditLossExpenseReversalAndAvailableForSaleAllowanceForCreditLoss	127500000	USD
	ntrs	Credit Loss Expense Reversal And Available For Sale Allowance For Credit Loss CreditLossExpenseReversalAndAvailableForSaleAllowanceForCreditLoss	-13500000	USD
	us-gaap	Noninterest Expense NoninterestExpense	3197200000	USD
	us-gaap	Noninterest Expense NoninterestExpense	3071200000	USD
	ntrs	Income Loss Before Income Taxes Including Fully Taxable Equivalent Adjustment IncomeLossBeforeIncomeTaxesIncludingFullyTaxableEquivalentAdjustment	1277900000	USD
	ntrs	Income Loss Before Income Taxes Including Fully Taxable Equivalent Adjustment IncomeLossBeforeIncomeTaxesIncludingFullyTaxableEquivalentAdjustment	1490800000	USD
	ntrs	Income Tax Expense Benefit Including Fully Taxable Equivalent Adjustment IncomeTaxExpenseBenefitIncludingFullyTaxableEquivalentAdjustment	309500000	USD
	ntrs	Income Tax Expense Benefit Including Fully Taxable Equivalent Adjustment IncomeTaxExpenseBenefitIncludingFullyTaxableEquivalentAdjustment	369700000	USD
	us-gaap	Net Income Loss NetIncomeLoss	968400000	USD
	us-gaap	Net Income Loss NetIncomeLoss	1121100000	USD
	ntrs	Percentage Of Consolidated Net Income PercentageOfConsolidatedNetIncome	1
	ntrs	Percentage Of Consolidated Net Income PercentageOfConsolidatedNetIncome	1
	ntrs	Segment Reporting Information Consolidated Average Assets SegmentReportingInformationConsolidatedAverageAssets	134645200000	USD
	ntrs	Segment Reporting Information Consolidated Average Assets SegmentReportingInformationConsolidatedAverageAssets	117364700000	USD
	ntrs	Segment Reporting Information Fully Taxable Equivalent Adjustment SegmentReportingInformationFullyTaxableEquivalentAdjustment	23700000	USD
	ntrs	Segment Reporting Information Fully Taxable Equivalent Adjustment SegmentReportingInformationFullyTaxableEquivalentAdjustment	23100000	USD
CY2020Q3	us-gaap	Preferred Stock Shares Authorized PreferredStockSharesAuthorized	10000000	shares
CY2020Q3	ntrs	Treasury Stock Sharebased Compensation Shares Acquired TreasuryStockSharebasedCompensationSharesAcquired	18534	shares
CY2020Q3	us-gaap	Treasury Stock Value Acquired Cost Method TreasuryStockValueAcquiredCostMethod	1500000	USD
CY2020Q3	us-gaap	Treasury Stock Acquired Average Cost Per Share TreasuryStockAcquiredAverageCostPerShare	81.02
	us-gaap	Treasury Stock Shares Acquired TreasuryStockSharesAcquired	3262621	shares
	ntrs	Treasury Stock Sharebased Compensation Shares Acquired TreasuryStockSharebasedCompensationSharesAcquired	518745	shares
	us-gaap	Treasury Stock Value Acquired Cost Method TreasuryStockValueAcquiredCostMethod	298500000	USD
	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	619200000	USD
	us-gaap	Treasury Stock Acquired Average Cost Per Share TreasuryStockAcquiredAverageCostPerShare	91.49
CY2018Q3	us-gaap	Stock Repurchase Program Number Of Shares Authorized To Be Repurchased StockRepurchaseProgramNumberOfSharesAuthorizedToBeRepurchased	25000000.0	shares
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
CY2019Q3	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	68800000	USD
	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	362700000	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
CY2019Q3	us-gaap	Other Comprehensive Income Loss Before Tax Portion Attributable To Parent OtherComprehensiveIncomeLossBeforeTaxPortionAttributableToParent	113200000	USD
CY2019Q3	us-gaap	Other Comprehensive Income Loss Tax Portion Attributable To Parent1 OtherComprehensiveIncomeLossTaxPortionAttributableToParent1	44400000	USD
CY2019Q3	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	68800000	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 Before Tax Portion Attributable To Parent OtherComprehensiveIncomeLossBeforeTaxPortionAttributableToParent	508400000	USD
	us-gaap	Other Comprehensive Income Loss Tax Portion Attributable To Parent1 OtherComprehensiveIncomeLossTaxPortionAttributableToParent1	145700000	USD
	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	362700000	USD
CY2020Q3	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	208106190	shares
CY2019Q3	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	213176809	shares
	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	208351088	shares
	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	215832347	shares
CY2020Q3	us-gaap	Net Income Loss NetIncomeLoss	294500000	USD
CY2019Q3	us-gaap	Net Income Loss NetIncomeLoss	384600000	USD
	us-gaap	Net Income Loss NetIncomeLoss	968400000	USD
	us-gaap	Net Income Loss NetIncomeLoss	1121100000	USD
CY2020Q3	us-gaap	Preferred Stock Dividends Income Statement Impact PreferredStockDividendsIncomeStatementImpact	16200000	USD
CY2019Q3	us-gaap	Preferred Stock Dividends Income Statement Impact PreferredStockDividendsIncomeStatementImpact	17400000	USD
	us-gaap	Preferred Stock Dividends Income Statement Impact PreferredStockDividendsIncomeStatementImpact	51500000	USD
	us-gaap	Preferred Stock Dividends Income Statement Impact PreferredStockDividendsIncomeStatementImpact	40600000	USD
CY2020Q3	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	278300000	USD
CY2019Q3	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	367200000	USD
	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	916900000	USD
	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	1080500000	USD
CY2020Q3	us-gaap	Undistributed Earnings Loss Allocated To Participating Securities Basic UndistributedEarningsLossAllocatedToParticipatingSecuritiesBasic	3300000	USD
CY2019Q3	us-gaap	Undistributed Earnings Loss Allocated To Participating Securities Basic UndistributedEarningsLossAllocatedToParticipatingSecuritiesBasic	4500000	USD
	us-gaap	Undistributed Earnings Loss Allocated To Participating Securities Basic UndistributedEarningsLossAllocatedToParticipatingSecuritiesBasic	10600000	USD
	us-gaap	Undistributed Earnings Loss Allocated To Participating Securities Basic UndistributedEarningsLossAllocatedToParticipatingSecuritiesBasic	12600000	USD
CY2020Q3	ntrs	Net Income Loss Allocated To Common Stockholders Basic NetIncomeLossAllocatedToCommonStockholdersBasic	275000000.0	USD
CY2019Q3	ntrs	Net Income Loss Allocated To Common Stockholders Basic NetIncomeLossAllocatedToCommonStockholdersBasic	362700000	USD
	ntrs	Net Income Loss Allocated To Common Stockholders Basic NetIncomeLossAllocatedToCommonStockholdersBasic	906300000	USD
	ntrs	Net Income Loss Allocated To Common Stockholders Basic NetIncomeLossAllocatedToCommonStockholdersBasic	1067900000	USD
CY2020Q3	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.32
CY2019Q3	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.70
	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	4.35
	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	4.95
CY2020Q3	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	208106190	shares
CY2019Q3	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	213176809	shares
	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	208351088	shares
	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	215832347	shares
CY2020Q3	us-gaap	Incremental Common Shares Attributable To Share Based Payment Arrangements IncrementalCommonSharesAttributableToShareBasedPaymentArrangements	582304	shares
CY2019Q3	us-gaap	Incremental Common Shares Attributable To Share Based Payment Arrangements IncrementalCommonSharesAttributableToShareBasedPaymentArrangements	1029767	shares
	us-gaap	Incremental Common Shares Attributable To Share Based Payment Arrangements IncrementalCommonSharesAttributableToShareBasedPaymentArrangements	672243	shares
	us-gaap	Incremental Common Shares Attributable To Share Based Payment Arrangements IncrementalCommonSharesAttributableToShareBasedPaymentArrangements	1031216	shares
CY2020Q3	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	208688494	shares
CY2019Q3	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	214206576	shares
	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	209023331	shares
	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	216863563	shares
CY2020Q3	us-gaap	Net Income Loss Available To Common Stockholders Diluted NetIncomeLossAvailableToCommonStockholdersDiluted	275000000.0	USD
CY2019Q3	us-gaap	Net Income Loss Available To Common Stockholders Diluted NetIncomeLossAvailableToCommonStockholdersDiluted	362700000	USD
	us-gaap	Net Income Loss Available To Common Stockholders Diluted NetIncomeLossAvailableToCommonStockholdersDiluted	906300000	USD
	us-gaap	Net Income Loss Available To Common Stockholders Diluted NetIncomeLossAvailableToCommonStockholdersDiluted	1067900000	USD
CY2020Q3	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.32
CY2019Q3	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.69
	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	4.34
	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	4.92
CY2019Q3	us-gaap	Antidilutive Securities Excluded From Computation Of Earnings Per Share Amount AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount	0	shares
CY2020Q3	us-gaap	Antidilutive Securities Excluded From Computation Of Earnings Per Share Amount AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount	0	shares
	us-gaap	Antidilutive Securities Excluded From Computation Of Earnings Per Share Amount AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount	0	shares
	us-gaap	Antidilutive Securities Excluded From Computation Of Earnings Per Share Amount AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount	0	shares
CY2020Q3	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	1003800000	USD
CY2019Q3	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	975500000	USD
	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	2968900000	USD
	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	2859900000	USD
CY2020Q3	us-gaap	Foreign Currency Transaction Gain Loss Before Tax ForeignCurrencyTransactionGainLossBeforeTax	61600000	USD
CY2019Q3	us-gaap	Foreign Currency Transaction Gain Loss Before Tax ForeignCurrencyTransactionGainLossBeforeTax	59700000	USD
	us-gaap	Foreign Currency Transaction Gain Loss Before Tax ForeignCurrencyTransactionGainLossBeforeTax	221800000	USD
	us-gaap	Foreign Currency Transaction Gain Loss Before Tax ForeignCurrencyTransactionGainLossBeforeTax	186400000	USD
CY2020Q3	ntrs	Treasury Management Fees TreasuryManagementFees	11600000	USD
CY2019Q3	ntrs	Treasury Management Fees TreasuryManagementFees	11200000	USD
	ntrs	Treasury Management Fees TreasuryManagementFees	34000000.0	USD
	ntrs	Treasury Management Fees TreasuryManagementFees	34100000	USD
CY2020Q3	ntrs	Security Commissionsand Trading Income SecurityCommissionsandTradingIncome	26000000.0	USD
CY2019Q3	ntrs	Security Commissionsand Trading Income SecurityCommissionsandTradingIncome	29100000	USD
	ntrs	Security Commissionsand Trading Income SecurityCommissionsandTradingIncome	100900000	USD
	ntrs	Security Commissionsand Trading Income SecurityCommissionsandTradingIncome	75800000	USD
CY2020Q3	us-gaap	Other Operating Income OtherOperatingIncome	53500000	USD
CY2019Q3	us-gaap	Other Operating Income OtherOperatingIncome	45100000	USD
	us-gaap	Other Operating Income OtherOperatingIncome	144400000	USD
	us-gaap	Other Operating Income OtherOperatingIncome	113000000.0	USD
CY2020Q3	us-gaap	Marketable Securities Gain Loss MarketableSecuritiesGainLoss	0	USD
CY2019Q3	us-gaap	Marketable Securities Gain Loss MarketableSecuritiesGainLoss	-400000	USD
	us-gaap	Marketable Securities Gain Loss MarketableSecuritiesGainLoss	100000	USD
CY2019Q3	us-gaap	Interest Income Securities Tax Exempt InterestIncomeSecuritiesTaxExempt	900000	USD
	us-gaap	Marketable Securities Gain Loss MarketableSecuritiesGainLoss	-900000	USD
CY2020Q3	ntrs	Other Noninterest Income OtherNoninterestIncome	152700000	USD
CY2019Q3	ntrs	Other Noninterest Income OtherNoninterestIncome	144700000	USD
	ntrs	Other Noninterest Income OtherNoninterestIncome	501200000	USD
	ntrs	Other Noninterest Income OtherNoninterestIncome	408400000	USD
CY2020Q3	us-gaap	Noninterest Income NoninterestIncome	1156500000	USD
CY2019Q3	us-gaap	Noninterest Income NoninterestIncome	1120200000	USD
	us-gaap	Noninterest Income NoninterestIncome	3470100000	USD
	us-gaap	Noninterest Income NoninterestIncome	3268300000	USD
CY2020Q3	ntrs	Security Commissionsand Trading Income SecurityCommissionsandTradingIncome	26000000.0	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
CY2019Q3	ntrs	Security Commissionsand Trading Income SecurityCommissionsandTradingIncome	29100000	USD
CY2019Q3	us-gaap	Other Operating Income OtherOperatingIncome	45100000	USD
	ntrs	Security Commissionsand Trading Income SecurityCommissionsandTradingIncome	75800000	USD
	us-gaap	Other Operating Income OtherOperatingIncome	113000000.0	USD
CY2020Q3	us-gaap	Contract With Customer Asset Net ContractWithCustomerAssetNet	918900000	USD
CY2019Q4	us-gaap	Contract With Customer Asset Net ContractWithCustomerAssetNet	903000000.0	USD
CY2020Q3	us-gaap	Interest And Fee Income Loans And Leases InterestAndFeeIncomeLoansAndLeases	167100000	USD
CY2019Q3	us-gaap	Interest And Fee Income Loans And Leases InterestAndFeeIncomeLoansAndLeases	291000000.0	USD
	us-gaap	Interest And Fee Income Loans And Leases InterestAndFeeIncomeLoansAndLeases	606400000	USD
	us-gaap	Interest And Fee Income Loans And Leases InterestAndFeeIncomeLoansAndLeases	889800000	USD
CY2020Q3	us-gaap	Interest Income Securities Taxable InterestIncomeSecuritiesTaxable	182600000	USD
CY2019Q3	us-gaap	Interest Income Securities Taxable InterestIncomeSecuritiesTaxable	265900000	USD
	us-gaap	Interest Income Securities Taxable InterestIncomeSecuritiesTaxable	632100000	USD
	us-gaap	Interest Income Securities Taxable InterestIncomeSecuritiesTaxable	812400000	USD
CY2020Q3	us-gaap	Interest Income Securities Tax Exempt InterestIncomeSecuritiesTaxExempt	300000	USD
	us-gaap	Interest Expense Deposits InterestExpenseDeposits	56700000	USD
	us-gaap	Interest Income Securities Tax Exempt InterestIncomeSecuritiesTaxExempt	1100000	USD
	us-gaap	Interest Income Securities Tax Exempt InterestIncomeSecuritiesTaxExempt	3100000	USD
CY2020Q3	us-gaap	Interest Income Deposits With Financial Institutions InterestIncomeDepositsWithFinancialInstitutions	2700000	USD
CY2019Q3	us-gaap	Interest Income Deposits With Financial Institutions InterestIncomeDepositsWithFinancialInstitutions	18600000	USD
	us-gaap	Interest Income Deposits With Financial Institutions InterestIncomeDepositsWithFinancialInstitutions	20000000.0	USD
	us-gaap	Interest Income Deposits With Financial Institutions InterestIncomeDepositsWithFinancialInstitutions	55700000	USD
CY2020Q3	ntrs	Interest Income Federal Reserve Deposits And Other InterestIncomeFederalReserveDepositsAndOther	2700000	USD
CY2019Q3	ntrs	Interest Income Federal Reserve Deposits And Other InterestIncomeFederalReserveDepositsAndOther	44400000	USD
	ntrs	Interest Income Federal Reserve Deposits And Other InterestIncomeFederalReserveDepositsAndOther	31300000	USD
	ntrs	Interest Income Federal Reserve Deposits And Other InterestIncomeFederalReserveDepositsAndOther	162800000	USD
CY2020Q3	us-gaap	Interest And Dividend Income Operating InterestAndDividendIncomeOperating	355400000	USD
CY2019Q3	us-gaap	Interest And Dividend Income Operating InterestAndDividendIncomeOperating	620800000	USD
	us-gaap	Interest And Dividend Income Operating InterestAndDividendIncomeOperating	1290900000	USD
	us-gaap	Interest And Dividend Income Operating InterestAndDividendIncomeOperating	1923800000	USD
CY2020Q3	us-gaap	Interest Expense Deposits InterestExpenseDeposits	-3500000	USD
CY2019Q3	us-gaap	Interest Expense Deposits InterestExpenseDeposits	122000000.0	USD
	us-gaap	Interest Expense Deposits InterestExpenseDeposits	403500000	USD
CY2020Q3	us-gaap	Interest Expense Federal Funds Purchased InterestExpenseFederalFundsPurchased	100000	USD
CY2019Q3	us-gaap	Interest Expense Federal Funds Purchased InterestExpenseFederalFundsPurchased	2400000	USD
	us-gaap	Interest Expense Federal Funds Purchased InterestExpenseFederalFundsPurchased	2100000	USD
	us-gaap	Interest Expense Federal Funds Purchased InterestExpenseFederalFundsPurchased	22800000	USD
CY2020Q3	us-gaap	Interest Expense Securities Sold Under Agreements To Repurchase InterestExpenseSecuritiesSoldUnderAgreementsToRepurchase	0	USD
CY2019Q3	us-gaap	Interest Expense Securities Sold Under Agreements To Repurchase InterestExpenseSecuritiesSoldUnderAgreementsToRepurchase	1600000	USD
	us-gaap	Interest Expense Securities Sold Under Agreements To Repurchase InterestExpenseSecuritiesSoldUnderAgreementsToRepurchase	1000000.0	USD
	us-gaap	Interest Expense Securities Sold Under Agreements To Repurchase InterestExpenseSecuritiesSoldUnderAgreementsToRepurchase	5400000	USD
CY2020Q3	us-gaap	Interest Expense Other Short Term Borrowings InterestExpenseOtherShortTermBorrowings	5000000.0	USD
CY2019Q3	us-gaap	Interest Expense Other Short Term Borrowings InterestExpenseOtherShortTermBorrowings	46000000.0	USD
	us-gaap	Interest Expense Other Short Term Borrowings InterestExpenseOtherShortTermBorrowings	40600000	USD
	us-gaap	Interest Expense Other Short Term Borrowings InterestExpenseOtherShortTermBorrowings	145200000	USD
CY2020Q3	ntrs	Interest Expense Senior Notes InterestExpenseSeniorNotes	19100000	USD
CY2019Q3	ntrs	Interest Expense Senior Notes InterestExpenseSeniorNotes	19600000	USD
	ntrs	Interest Expense Senior Notes InterestExpenseSeniorNotes	57000000.0	USD
	ntrs	Interest Expense Senior Notes InterestExpenseSeniorNotes	54000000.0	USD
CY2020Q3	us-gaap	Interest Expense Other Long Term Debt InterestExpenseOtherLongTermDebt	5700000	USD
CY2019Q3	us-gaap	Interest Expense Other Long Term Debt InterestExpenseOtherLongTermDebt	9400000	USD
	us-gaap	Interest Expense Other Long Term Debt InterestExpenseOtherLongTermDebt	21100000	USD
	us-gaap	Interest Expense Other Long Term Debt InterestExpenseOtherLongTermDebt	29400000	USD
CY2020Q3	us-gaap	Interest Expense Junior Subordinated Debentures InterestExpenseJuniorSubordinatedDebentures	400000	USD
CY2019Q3	us-gaap	Interest Expense Junior Subordinated Debentures InterestExpenseJuniorSubordinatedDebentures	2100000	USD
	us-gaap	Interest Expense Junior Subordinated Debentures InterestExpenseJuniorSubordinatedDebentures	3600000	USD
	us-gaap	Interest Expense Junior Subordinated Debentures InterestExpenseJuniorSubordinatedDebentures	6400000	USD
CY2020Q3	us-gaap	Interest Expense InterestExpense	26800000	USD
CY2019Q3	us-gaap	Interest Expense InterestExpense	203100000	USD
	us-gaap	Interest Expense InterestExpense	182100000	USD
	us-gaap	Interest Expense InterestExpense	666700000	USD
CY2020Q3	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	328600000	USD
CY2019Q3	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	417700000	USD
	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	1108800000	USD
	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	1257100000	USD
CY2020Q3	us-gaap	Defined Benefit Plan Plan Amendments DefinedBenefitPlanPlanAmendments	-12600000	USD
CY2020Q3	ntrs	Defined Benefit Plan Benefit Obligation Increase Decrease For Amortization Period Adjustment DefinedBenefitPlanBenefitObligationIncreaseDecreaseForAmortizationPeriodAdjustment	-300000	USD
CY2020Q3	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	13900000	USD
CY2019Q3	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	17300000	USD
	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	82800000	USD
	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	91300000	USD
CY2020Q3	us-gaap	Employee Service Share Based Compensation Tax Benefit From Compensation Expense EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense	3500000	USD
CY2019Q3	us-gaap	Employee Service Share Based Compensation Tax Benefit From Compensation Expense EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense	4300000	USD
	us-gaap	Employee Service Share Based Compensation Tax Benefit From Compensation Expense EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense	20600000	USD
	us-gaap	Employee Service Share Based Compensation Tax Benefit From Compensation Expense EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense	22700000	USD
CY2020Q3	us-gaap	Variable Interest Entity Entity Maximum Loss Exposure Amount VariableInterestEntityEntityMaximumLossExposureAmount	0	USD
CY2020Q3	us-gaap	Affordable Housing Tax Credits And Other Tax Benefits Amount AffordableHousingTaxCreditsAndOtherTaxBenefitsAmount	20700000	USD
CY2019Q3	us-gaap	Affordable Housing Tax Credits And Other Tax Benefits Amount AffordableHousingTaxCreditsAndOtherTaxBenefitsAmount	16400000	USD
	us-gaap	Affordable Housing Tax Credits And Other Tax Benefits Amount AffordableHousingTaxCreditsAndOtherTaxBenefitsAmount	59400000	USD
	us-gaap	Affordable Housing Tax Credits And Other Tax Benefits Amount AffordableHousingTaxCreditsAndOtherTaxBenefitsAmount	49200000	USD
CY2020Q3	us-gaap	Investment Company Financial Support To Investee Contractually Required Amount InvestmentCompanyFinancialSupportToInvesteeContractuallyRequiredAmount	0	USD
CY2020Q3	us-gaap	Fair Value Investments Entities That Calculate Net Asset Value Per Share Unfunded Committments FairValueInvestmentsEntitiesThatCalculateNetAssetValuePerShareUnfundedCommittments	73300000	USD
CY2019Q4	us-gaap	Fair Value Investments Entities That Calculate Net Asset Value Per Share Unfunded Committments FairValueInvestmentsEntitiesThatCalculateNetAssetValuePerShareUnfundedCommittments	0	USD
	us-gaap	Loss Contingency Disclosures LossContingencyDisclosures	Commitments and Contingent Liabilities<div style="text-align:justify;margin-top:12pt;"><span style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%;">Commitments, Letters of Credit and Indemnifications. </span><span style="background-color:rgb(255,255,255, 0.0);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.</span></div><div style="text-align:justify;margin-top:12pt;"><span style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;">Legally binding commitments to extend credit 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. Legally binding commitments to extend credit totaled $26.4 billion and $24.4 billion as of September 30, 2020 and December 31, 2019, respectively.</span></div><div style="text-align:justify;margin-top:12pt;"><span style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;">Standby letters of credit 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. Standby letters of credit outstanding and financial guarantees were $2.1 billion and $2.4 billion as of September 30, 2020 and December 31, 2019, respectively. Financial guarantees are issued by Northern Trust to guarantee the performance of a client to a third party under certain arrangements.</span></div><div style="text-align:justify;margin-top:12pt;margin-bottom:6pt;"><span style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;">As part of its securities custody activities and at the direction of its clients, Northern Trust lends securities owned by clients to borrowers who are reviewed and approved by the Northern Trust Capital Markets Credit Committee. 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 </span></div><div style="text-align:justify;margin-top:12pt;margin-bottom:6pt;"><span style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;">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, 2020 and December 31, 2019 subject to indemnification was $148.3 billion and $138.1 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, 2020 or December 31, 2019, related to these indemnifications.</span></div><div style="text-align:justify;margin-top:12pt;"><span style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%;">Legal Proceedings.</span><span style="background-color:rgb(255,255,255, 0.0);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 asserted. In regulatory matters, claims for disgorgement, restitution, penalties and/or other remedial actions or sanctions may be sought.</span></div><div style="text-align:justify;margin-top:12pt;"><span style="background-color:rgb(255,255,255, 0.0);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="text-align:justify;"><span><br/></span></div><div style="text-align:justify;"><span style="background-color:rgb(255,255,255, 0.0);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="text-align:justify;margin-top:12pt;"><span style="background-color:rgb(255,255,255, 0.0);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="text-align:justify;margin-top:12pt;"><span style="background-color:rgb(255,255,255, 0.0);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="text-align:justify;margin-top:12pt;"><span style="background-color:rgb(255,255,255, 0.0);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, 2020, the Corporation has estimated the range of reasonably possible loss for these matters to be from zero to approximately $15 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="text-align:justify;margin-top:12pt;"><span style="background-color:rgb(255,255,255, 0.0);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="text-align:justify;margin-top:12pt;"><span style="background-color:rgb(255,255,255, 0.0);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. The Public Prosecutor’s Office of France has appealed the appellate court’s decision to the Cour de Cassation, the highest court in France. 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="text-align:justify;margin-top:12pt;"><span style="background-color:rgb(255,255,255, 0.0);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="background-color:rgb(255,255,255, 0.0);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 </span></div><div style="text-align:justify;margin-top:12pt;"><span style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;">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="text-align:justify;margin-top:12pt;"><span style="background-color:rgb(255,255,255, 0.0);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><div style="text-align:justify;margin-top:12pt;"><span style="background-color:rgb(255,255,255, 0.0);color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;">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, 2020 and December 31, 2019.</span></div>
CY2020Q3	us-gaap	Fair Value Disclosure Offbalance Sheet Risks Amount Liability FairValueDisclosureOffbalanceSheetRisksAmountLiability	26400000000	USD
CY2019Q4	us-gaap	Fair Value Disclosure Offbalance Sheet Risks Amount Liability FairValueDisclosureOffbalanceSheetRisksAmountLiability	24400000000	USD
CY2020Q3	us-gaap	Letters Of Credit Outstanding Amount LettersOfCreditOutstandingAmount	2100000000	USD
CY2019Q4	us-gaap	Letters Of Credit Outstanding Amount LettersOfCreditOutstandingAmount	2400000000	USD
CY2020Q3	ntrs	Securities Lending Related Collateral Maintenance SecuritiesLendingRelatedCollateralMaintenance	1
CY2020Q3	us-gaap	Loss Contingency Accrual At Carrying Value LossContingencyAccrualAtCarryingValue	0	USD
CY2020Q3	us-gaap	Derivative Notional Amount DerivativeNotionalAmount	281329700000	USD
CY2020Q3	us-gaap	Derivative Asset Fair Value Gross Asset Including Not Subject To Master Netting Arrangement DerivativeAssetFairValueGrossAssetIncludingNotSubjectToMasterNettingArrangement	2613200000	USD
CY2020Q3	us-gaap	Derivative Liability Fair Value Gross Liability Including Not Subject To Master Netting Arrangement DerivativeLiabilityFairValueGrossLiabilityIncludingNotSubjectToMasterNettingArrangement	2500800000	USD
CY2019Q4	us-gaap	Derivative Notional Amount DerivativeNotionalAmount	310600700000	USD
CY2019Q4	us-gaap	Derivative Asset Fair Value Gross Asset Including Not Subject To Master Netting Arrangement DerivativeAssetFairValueGrossAssetIncludingNotSubjectToMasterNettingArrangement	3387700000	USD
CY2019Q4	us-gaap	Derivative Liability Fair Value Gross Liability Including Not Subject To Master Netting Arrangement DerivativeLiabilityFairValueGrossLiabilityIncludingNotSubjectToMasterNettingArrangement	3313000000.0	USD
CY2020Q3	us-gaap	Derivative Asset Fair Value Gross Liability DerivativeAssetFairValueGrossLiability	1408300000	USD
CY2020Q3	us-gaap	Derivative Liability Fair Value Gross Asset DerivativeLiabilityFairValueGrossAsset	1603300000	USD
CY2019Q4	us-gaap	Derivative Asset Fair Value Gross Liability DerivativeAssetFairValueGrossLiability	2338000000.0	USD
CY2019Q4	us-gaap	Derivative Liability Fair Value Gross Asset DerivativeLiabilityFairValueGrossAsset	1618400000	USD
CY2020Q3	us-gaap	Derivative Assets DerivativeAssets	1204900000	USD
CY2020Q3	us-gaap	Derivative Liabilities DerivativeLiabilities	897500000	USD
CY2019Q4	us-gaap	Derivative Assets DerivativeAssets	1049700000	USD
CY2019Q4	us-gaap	Derivative Liabilities DerivativeLiabilities	1694600000	USD
	us-gaap	Gain Loss On Discontinuation Of Cash Flow Hedge Due To Forecasted Transaction Probable Of Not Occurring Net GainLossOnDiscontinuationOfCashFlowHedgeDueToForecastedTransactionProbableOfNotOccurringNet	0	USD
CY2020Q3	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
CY2019Q3	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
CY2019Q4	us-gaap	Hedged Asset Fair Value Hedge Cumulative Increase Decrease HedgedAssetFairValueHedgeCumulativeIncreaseDecrease	3300000	USD
CY2020Q3	us-gaap	Interest And Dividend Income Operating InterestAndDividendIncomeOperating	355400000	USD
CY2019Q3	us-gaap	Interest And Dividend Income Operating InterestAndDividendIncomeOperating	620800000	USD
CY2020Q3	us-gaap	Interest Expense InterestExpense	26800000	USD
CY2019Q3	us-gaap	Interest Expense InterestExpense	203100000	USD
CY2020Q3	us-gaap	Noninterest Income Other Operating Income NoninterestIncomeOtherOperatingIncome	53500000	USD
CY2019Q3	us-gaap	Noninterest Income Other Operating Income NoninterestIncomeOtherOperatingIncome	45100000	USD
	us-gaap	Interest And Dividend Income Operating InterestAndDividendIncomeOperating	1290900000	USD
	us-gaap	Interest And Dividend Income Operating InterestAndDividendIncomeOperating	1923800000	USD
	us-gaap	Interest Expense InterestExpense	182100000	USD
	us-gaap	Interest Expense InterestExpense	666700000	USD
	us-gaap	Noninterest Income Other Operating Income NoninterestIncomeOtherOperatingIncome	144400000	USD
	us-gaap	Noninterest Income Other Operating Income NoninterestIncomeOtherOperatingIncome	113000000.0	USD
CY2020Q3	us-gaap	Hedged Asset Fair Value Hedge HedgedAssetFairValueHedge	2826200000	USD
CY2020Q3	us-gaap	Hedged Asset Fair Value Hedge Cumulative Increase Decrease HedgedAssetFairValueHedgeCumulativeIncreaseDecrease	63300000	USD
CY2019Q4	us-gaap	Hedged Asset Fair Value Hedge HedgedAssetFairValueHedge	2981000000.0	USD
CY2020Q3	us-gaap	Hedged Liability Fair Value Hedge HedgedLiabilityFairValueHedge	2745000000.0	USD
CY2020Q3	us-gaap	Hedged Liability Fair Value Hedge Cumulative Increase Decrease HedgedLiabilityFairValueHedgeCumulativeIncreaseDecrease	261800000	USD
CY2019Q4	us-gaap	Hedged Liability Fair Value Hedge HedgedLiabilityFairValueHedge	1748500000	USD
CY2019Q4	us-gaap	Hedged Liability Fair Value Hedge Cumulative Increase Decrease HedgedLiabilityFairValueHedgeCumulativeIncreaseDecrease	126900000	USD
CY2020Q3	us-gaap	Fair Value Hedges At Fair Value Net FairValueHedgesAtFairValueNet	5571200000	USD
CY2020Q3	ntrs	Hedged Asset Liability Fair Value Hedge Cumulative Increase Decrease Net HedgedAssetLiabilityFairValueHedgeCumulativeIncreaseDecreaseNet	325100000	USD
CY2019Q4	us-gaap	Fair Value Hedges At Fair Value Net FairValueHedgesAtFairValueNet	4729500000	USD
CY2019Q4	ntrs	Hedged Asset Liability Fair Value Hedge Cumulative Increase Decrease Net HedgedAssetLiabilityFairValueHedgeCumulativeIncreaseDecreaseNet	130200000	USD
CY2020Q3	ntrs	Hedged Asset Fair Value Hedge Discontinued Cumulative Increase Decrease HedgedAssetFairValueHedgeDiscontinuedCumulativeIncreaseDecrease	6700000	USD
CY2020Q3	ntrs	Hedged Liability Fair Value Hedge Discontinued Cumulative Increase Decrease HedgedLiabilityFairValueHedgeDiscontinuedCumulativeIncreaseDecrease	0	USD
CY2019Q4	ntrs	Hedged Asset Fair Value Hedge Discontinued Cumulative Increase Decrease HedgedAssetFairValueHedgeDiscontinuedCumulativeIncreaseDecrease	1500000	USD
CY2019Q4	ntrs	Hedged Liability Fair Value Hedge Discontinued Cumulative Increase Decrease HedgedLiabilityFairValueHedgeDiscontinuedCumulativeIncreaseDecrease	0	USD
CY2020Q3	ntrs	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Before Reclassification After Ta OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAfterTa	-117400000	USD
CY2019Q3	ntrs	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Before Reclassification After Ta OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAfterTa	107600000	USD
	ntrs	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Before Reclassification After Ta OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAfterTa	-29800000	USD
	ntrs	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Before Reclassification After Ta OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAfterTa	144100000	USD
CY2020Q3	us-gaap	Securities Purchased Under Agreements To Resell SecuritiesPurchasedUnderAgreementsToResell	1533400000	USD
CY2020Q3	ntrs	Derivative Asset Securities Purchased Under Agreements To Resell Collateral DerivativeAssetSecuritiesPurchasedUnderAgreementsToResellCollateral	1533400000	USD
CY2020Q3	us-gaap	Derivative Fair Value Of Derivative Asset DerivativeFairValueOfDerivativeAsset	2098000000.0	USD
CY2020Q3	us-gaap	Derivative Asset Fair Value Gross Liability DerivativeAssetFairValueGrossLiability	1408300000	USD
CY2020Q3	us-gaap	Derivative Fair Value Of Derivative Asset Amount Not Offset Against Collateral DerivativeFairValueOfDerivativeAssetAmountNotOffsetAgainstCollateral	689700000	USD
CY2020Q3	us-gaap	Derivative Collateral Obligation To Return Cash DerivativeCollateralObligationToReturnCash	29700000	USD
CY2020Q3	us-gaap	Derivative Fair Value Of Derivative Asset Amount Offset Against Collateral DerivativeFairValueOfDerivativeAssetAmountOffsetAgainstCollateral	660000000.0	USD
CY2020Q3	us-gaap	Derivative Asset Not Subject To Master Netting Arrangement DerivativeAssetNotSubjectToMasterNettingArrangement	515200000	USD
CY2020Q3	us-gaap	Derivative Asset Not Subject To Master Netting Arrangement DerivativeAssetNotSubjectToMasterNettingArrangement	515200000	USD
CY2020Q3	us-gaap	Derivative Asset Not Subject To Master Netting Arrangement Deduction DerivativeAssetNotSubjectToMasterNettingArrangementDeduction	900000	USD
CY2020Q3	ntrs	Derivative Asset Not Subjectto Master Netting Arrangement Net DerivativeAssetNotSubjecttoMasterNettingArrangementNet	514300000	USD
CY2020Q3	us-gaap	Derivative Asset Fair Value Gross Asset Including Not Subject To Master Netting Arrangement DerivativeAssetFairValueGrossAssetIncludingNotSubjectToMasterNettingArrangement	2613200000	USD
CY2020Q3	us-gaap	Derivative Asset Fair Value Gross Liability DerivativeAssetFairValueGrossLiability	1408300000	USD
CY2020Q3	us-gaap	Derivative Assets DerivativeAssets	1204900000	USD
CY2020Q3	ntrs	Derivative Asset Not Offset DerivativeAssetNotOffset	30600000	USD
CY2020Q3	us-gaap	Derivative Asset Fair Value Offset Against Collateral Net Of Not Subject To Master Netting Arrangement Policy Election DerivativeAssetFairValueOffsetAgainstCollateralNetOfNotSubjectToMasterNettingArrangementPolicyElection	1174300000	USD
CY2020Q3	us-gaap	Securities Purchased Under Agreements To Resell Gross SecuritiesPurchasedUnderAgreementsToResellGross	1533400000	USD
CY2019Q4	us-gaap	Derivative Fair Value Of Derivative Asset DerivativeFairValueOfDerivativeAsset	2844000000.0	USD
CY2019Q4	us-gaap	Derivative Asset Fair Value Gross Liability DerivativeAssetFairValueGrossLiability	2338000000.0	USD
CY2019Q4	us-gaap	Derivative Fair Value Of Derivative Asset Amount Not Offset Against Collateral DerivativeFairValueOfDerivativeAssetAmountNotOffsetAgainstCollateral	506000000.0	USD
CY2019Q4	us-gaap	Derivative Collateral Obligation To Return Cash DerivativeCollateralObligationToReturnCash	16500000	USD
CY2019Q4	us-gaap	Derivative Fair Value Of Derivative Asset Amount Offset Against Collateral DerivativeFairValueOfDerivativeAssetAmountOffsetAgainstCollateral	489500000	USD
CY2019Q4	us-gaap	Derivative Asset Not Subject To Master Netting Arrangement DerivativeAssetNotSubjectToMasterNettingArrangement	543700000	USD
CY2019Q4	us-gaap	Derivative Asset Not Subject To Master Netting Arrangement DerivativeAssetNotSubjectToMasterNettingArrangement	543700000	USD
CY2019Q4	us-gaap	Derivative Asset Not Subject To Master Netting Arrangement Deduction DerivativeAssetNotSubjectToMasterNettingArrangementDeduction	300000	USD
CY2019Q4	ntrs	Derivative Asset Not Subjectto Master Netting Arrangement Net DerivativeAssetNotSubjecttoMasterNettingArrangementNet	543400000	USD
CY2019Q4	us-gaap	Derivative Asset Fair Value Gross Asset Including Not Subject To Master Netting Arrangement DerivativeAssetFairValueGrossAssetIncludingNotSubjectToMasterNettingArrangement	3387700000	USD
CY2019Q4	us-gaap	Derivative Asset Fair Value Gross Liability DerivativeAssetFairValueGrossLiability	2338000000.0	USD
CY2019Q4	us-gaap	Derivative Assets DerivativeAssets	1049700000	USD
CY2019Q4	ntrs	Derivative Asset Not Offset DerivativeAssetNotOffset	16800000	USD
CY2019Q4	us-gaap	Derivative Asset Fair Value Offset Against Collateral Net Of Not Subject To Master Netting Arrangement Policy Election DerivativeAssetFairValueOffsetAgainstCollateralNetOfNotSubjectToMasterNettingArrangementPolicyElection	1032900000	USD
CY2019Q4	us-gaap	Securities Purchased Under Agreements To Resell Gross SecuritiesPurchasedUnderAgreementsToResellGross	707800000	USD
CY2019Q4	us-gaap	Securities Purchased Under Agreements To Resell SecuritiesPurchasedUnderAgreementsToResell	707800000	USD
CY2019Q4	ntrs	Derivative Asset Securities Purchased Under Agreements To Resell Collateral DerivativeAssetSecuritiesPurchasedUnderAgreementsToResellCollateral	707800000	USD
CY2020Q3	ntrs	Other Assets Excluding Derivatives And Non Financial Instruments OtherAssetsExcludingDerivativesAndNonFinancialInstruments	7300000000	USD
CY2019Q4	ntrs	Other Assets Excluding Derivatives And Non Financial Instruments OtherAssetsExcludingDerivativesAndNonFinancialInstruments	7400000000	USD
CY2020Q3	us-gaap	Federal Funds Sold FederalFundsSold	0	USD
CY2019Q4	us-gaap	Federal Funds Sold FederalFundsSold	5000000.0	USD
CY2020Q3	us-gaap	Derivative Fair Value Of Derivative Liability DerivativeFairValueOfDerivativeLiability	2143800000	USD
CY2020Q3	us-gaap	Derivative Liability Fair Value Gross Asset DerivativeLiabilityFairValueGrossAsset	1603300000	USD
CY2020Q3	us-gaap	Derivative Fair Value Of Derivative Liability Amount Not Offset Against Collateral DerivativeFairValueOfDerivativeLiabilityAmountNotOffsetAgainstCollateral	540500000	USD
CY2020Q3	us-gaap	Derivative Collateral Right To Reclaim Cash DerivativeCollateralRightToReclaimCash	0	USD
CY2020Q3	us-gaap	Derivative Fair Value Of Derivative Liability Amount Offset Against Collateral DerivativeFairValueOfDerivativeLiabilityAmountOffsetAgainstCollateral	540500000	USD
CY2020Q3	us-gaap	Derivative Liability Not Subject To Master Netting Arrangement DerivativeLiabilityNotSubjectToMasterNettingArrangement	357000000.0	USD
CY2020Q3	us-gaap	Derivative Liability Not Subject To Master Netting Arrangement DerivativeLiabilityNotSubjectToMasterNettingArrangement	357000000.0	USD
CY2020Q3	us-gaap	Derivative Liability Not Subject To Master Netting Arrangement Deduction DerivativeLiabilityNotSubjectToMasterNettingArrangementDeduction	0	USD
CY2020Q3	ntrs	Derivative Liability Not Subject To Master Netting Arrangement Net DerivativeLiabilityNotSubjectToMasterNettingArrangementNet	357000000.0	USD
CY2020Q3	us-gaap	Derivative Liability Fair Value Gross Liability Including Not Subject To Master Netting Arrangement DerivativeLiabilityFairValueGrossLiabilityIncludingNotSubjectToMasterNettingArrangement	2500800000	USD
CY2020Q3	us-gaap	Derivative Liability Fair Value Gross Asset DerivativeLiabilityFairValueGrossAsset	1603300000	USD
CY2020Q3	us-gaap	Derivative Liabilities DerivativeLiabilities	897500000	USD
CY2020Q3	ntrs	Derivative Liability Not Offset DerivativeLiabilityNotOffset	0	USD
CY2020Q3	us-gaap	Derivative Liability Fair Value Offset Against Collateral Net Of Not Subject To Master Netting Arrangement Policy Election DerivativeLiabilityFairValueOffsetAgainstCollateralNetOfNotSubjectToMasterNettingArrangementPolicyElection	897500000	USD
CY2020Q3	us-gaap	Securities Sold Under Agreements To Repurchase Gross SecuritiesSoldUnderAgreementsToRepurchaseGross	269800000	USD
CY2020Q3	us-gaap	Securities Sold Under Agreements To Repurchase SecuritiesSoldUnderAgreementsToRepurchase	269800000	USD
CY2020Q3	ntrs	Derivative Liability Securities Sold Under Agreement To Repurchase Collateral DerivativeLiabilitySecuritiesSoldUnderAgreementToRepurchaseCollateral	269800000	USD
CY2019Q4	us-gaap	Derivative Fair Value Of Derivative Liability DerivativeFairValueOfDerivativeLiability	2312400000	USD
CY2019Q4	us-gaap	Derivative Liability Fair Value Gross Asset DerivativeLiabilityFairValueGrossAsset	1618400000	USD
CY2019Q4	us-gaap	Derivative Fair Value Of Derivative Liability Amount Not Offset Against Collateral DerivativeFairValueOfDerivativeLiabilityAmountNotOffsetAgainstCollateral	694000000.0	USD
CY2019Q4	us-gaap	Derivative Collateral Right To Reclaim Cash DerivativeCollateralRightToReclaimCash	100000	USD
CY2019Q4	us-gaap	Derivative Fair Value Of Derivative Liability Amount Offset Against Collateral DerivativeFairValueOfDerivativeLiabilityAmountOffsetAgainstCollateral	693900000	USD
CY2019Q4	us-gaap	Derivative Liability Not Subject To Master Netting Arrangement DerivativeLiabilityNotSubjectToMasterNettingArrangement	1000600000	USD
CY2019Q4	us-gaap	Derivative Liability Not Subject To Master Netting Arrangement DerivativeLiabilityNotSubjectToMasterNettingArrangement	1000600000	USD
CY2019Q4	ntrs	Derivative Liability Not Subject To Master Netting Arrangement Net DerivativeLiabilityNotSubjectToMasterNettingArrangementNet	1000600000	USD
CY2019Q4	us-gaap	Derivative Liability Fair Value Gross Liability Including Not Subject To Master Netting Arrangement DerivativeLiabilityFairValueGrossLiabilityIncludingNotSubjectToMasterNettingArrangement	3313000000.0	USD
CY2019Q4	us-gaap	Derivative Liability Fair Value Gross Asset DerivativeLiabilityFairValueGrossAsset	1618400000	USD
CY2019Q4	us-gaap	Derivative Liabilities DerivativeLiabilities	1694600000	USD
CY2019Q4	ntrs	Derivative Liability Not Offset DerivativeLiabilityNotOffset	100000	USD
CY2019Q4	us-gaap	Derivative Liability Fair Value Offset Against Collateral Net Of Not Subject To Master Netting Arrangement Policy Election DerivativeLiabilityFairValueOffsetAgainstCollateralNetOfNotSubjectToMasterNettingArrangementPolicyElection	1694500000	USD
CY2019Q4	us-gaap	Securities Sold Under Agreements To Repurchase Gross SecuritiesSoldUnderAgreementsToRepurchaseGross	489700000	USD
CY2019Q4	us-gaap	Securities Sold Under Agreements To Repurchase SecuritiesSoldUnderAgreementsToRepurchase	489700000	USD
CY2019Q4	ntrs	Derivative Liability Securities Sold Under Agreement To Repurchase Collateral DerivativeLiabilitySecuritiesSoldUnderAgreementToRepurchaseCollateral	489700000	USD
CY2020Q3	ntrs	Other Liabilities Excluding Derivatives And Non Financial Instruments OtherLiabilitiesExcludingDerivativesAndNonFinancialInstruments	3600000000	USD
CY2019Q4	ntrs	Other Liabilities Excluding Derivatives And Non Financial Instruments OtherLiabilitiesExcludingDerivativesAndNonFinancialInstruments	3100000000	USD
CY2020Q3	us-gaap	Derivative Net Liability Position Aggregate Fair Value DerivativeNetLiabilityPositionAggregateFairValue	565500000	USD
CY2019Q4	us-gaap	Derivative Net Liability Position Aggregate Fair Value DerivativeNetLiabilityPositionAggregateFairValue	766200000	USD
CY2020Q3	us-gaap	Collateral Already Posted Aggregate Fair Value CollateralAlreadyPostedAggregateFairValue	184400000	USD
CY2019Q4	us-gaap	Collateral Already Posted Aggregate Fair Value CollateralAlreadyPostedAggregateFairValue	327100000	USD
CY2020Q3	us-gaap	Assets Needed For Immediate Settlement Aggregate Fair Value AssetsNeededForImmediateSettlementAggregateFairValue	381100000	USD
CY2019Q4	us-gaap	Assets Needed For Immediate Settlement Aggregate Fair Value AssetsNeededForImmediateSettlementAggregateFairValue	439100000	USD

Files In Submission

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2020 Q3 Form 10-Q Financial Statement

#000007312420000244 Filed on October 27, 2020

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$NTRS NORTHERN TRUST CORP Stock $ntrs

2020 Q3 Form 10-Q Financial Statement

#000007312420000244 Filed on October 27, 2020

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$NTRS
NORTHERN TRUST CORP Stock $ntrs