$CMA
COMERICA INC /NEW/ Stock $cma

$cma Overview Financials Valuation SEC Filings Company Website

2019 Form 10-K Financial Statement

#000002841220000034 Filed on February 11, 2020

Income Statement

Concept	2019	2018 Q4	2018 Q3
Revenue	$2.807B	$704.0M	$675.0M
YoY Change	7.18%	8.31%	16.58%
Cost Of Revenue
YoY Change
Gross Profit
YoY Change
Gross Profit Margin
Selling, General & Admin
YoY Change
% of Gross Profit
Research & Development
YoY Change
% of Gross Profit
Depreciation & Amortization	$114.0M	$30.00M	$30.00M
YoY Change	-5.0%	0.0%	-3.23%
% of Gross Profit
Operating Expenses
YoY Change
Operating Profit
YoY Change
Interest Expense	$468.0M	$90.00M	$76.00M
YoY Change	75.28%	50.0%	130.3%
% of Operating Profit
Other Income/Expense, Net
YoY Change
Pretax Income	-$1.538B	$400.0M	$381.0M
YoY Change	-200.2%	21.21%	14.07%
Income Tax	$336.0M	$90.00M	$63.00M
% Of Pretax Income		22.5%	16.54%
Net Earnings	$1.202B	$310.0M	$318.0M
YoY Change	-2.67%	-4.91%	40.71%
Net Earnings / Revenue	42.82%	44.03%	47.11%
Basic Earnings Per Share	$7.98	$1.91	$1.89
Diluted Earnings Per Share	$7.90	$1.88	$1.86
COMMON SHARES
Basic Shares Outstanding	150.0M shares	161.7M shares	167.0M shares
Diluted Shares Outstanding	151.0M shares		170.0M shares

Balance Sheet

Concept	2019	2018 Q4	2018 Q3
SHORT-TERM ASSETS
Cash & Short-Term Investments
YoY Change
Cash & Equivalents		$4.561B	$5.839B
Short-Term Investments
Other Short-Term Assets
YoY Change
Inventory
Prepaid Expenses
Receivables
Other Receivables
Total Short-Term Assets
YoY Change
LONG-TERM ASSETS
Property, Plant & Equipment	$786.0M	$475.0M	$472.0M
YoY Change	65.47%	1.93%	1.07%
Goodwill		$635.0M
YoY Change		0.0%
Intangibles
YoY Change
Long-Term Investments
YoY Change
Other Assets
YoY Change
Total Long-Term Assets
YoY Change
TOTAL ASSETS
Total Short-Term Assets
Total Long-Term Assets
Total Assets	$73.40B	$70.82B	$71.45B
YoY Change	3.65%	-1.05%	-0.79%
SHORT-TERM LIABILITIES
YoY Change
Accounts Payable
YoY Change
Accrued Expenses	$1.440B	$1.243B	$1.154B
YoY Change	15.85%	16.28%	13.36%
Deferred Revenue
YoY Change
Short-Term Debt	$71.00M	$44.00M	$84.00M
YoY Change	61.36%	340.0%	-83.5%
Long-Term Debt Due
YoY Change
Total Short-Term Liabilities	$1.440B	$1.243B	$1.154B
YoY Change	15.85%	16.28%	13.36%
LONG-TERM LIABILITIES
Long-Term Debt	$3.469B	$2.663B	$2.618B
YoY Change	30.27%	46.16%	42.51%
Other Long-Term Liabilities
YoY Change
Total Long-Term Liabilities	$3.469B	$2.663B	$2.618B
YoY Change	30.27%	46.16%	42.51%
TOTAL LIABILITIES
Total Short-Term Liabilities	$1.440B	$1.243B	$1.154B
Total Long-Term Liabilities	$3.469B	$2.663B	$2.618B
Total Liabilities	$66.08B	$63.31B	$63.66B
YoY Change	4.37%	-0.46%	-0.5%
SHAREHOLDERS EQUITY
Retained Earnings		$8.781B	$8.587B
YoY Change		11.34%	10.86%
Common Stock		$3.289B	$3.285B
YoY Change		0.8%	0.98%
Preferred Stock
YoY Change
Treasury Stock (at cost)		$3.954B	$3.475B
YoY Change		44.52%	33.35%
Treasury Stock Shares		68.08M shares	62.22M shares
Shareholders Equity	$7.327B	$7.507B	$7.786B
YoY Change
Total Liabilities & Shareholders Equity	$73.40B	$70.82B	$71.45B
YoY Change	3.65%	-1.05%	-0.79%

Cashflow Statement

Concept	2019	2018 Q4	2018 Q3
OPERATING ACTIVITIES
Net Income	$1.202B	$310.0M	$318.0M
YoY Change	-2.67%	-4.91%	40.71%
Depreciation, Depletion And Amortization	$114.0M	$30.00M	$30.00M
YoY Change	-5.0%	0.0%	-3.23%
Cash From Operating Activities	$1.090B	$649.0M	$353.0M
YoY Change	-32.55%	176.17%	76.5%
INVESTING ACTIVITIES
Capital Expenditures	-$86.00M	-$25.00M	-$24.00M
YoY Change	-4.44%	-3.85%	50.0%
Acquisitions
YoY Change
Other Investing Activities	-$2.000M	-$1.158B	$767.0M
YoY Change	-200.0%	-1358.7%	243.95%
Cash From Investing Activities	-$494.0M	-$1.183B	$743.0M
YoY Change	-142.73%	-1892.42%	258.94%
FINANCING ACTIVITIES
Cash Dividend Paid
YoY Change
Common Stock Issuance & Retirement, Net	$1.376B
YoY Change	7.0%
Debt Paid & Issued, Net	$350.0M
YoY Change
Cash From Financing Activities	$661.0M	-744.0M	-917.0M
YoY Change	-137.9%	12.73%	-652.41%
NET CHANGE
Cash From Operating Activities	$1.090B	649.0M	353.0M
Cash From Investing Activities	-$494.0M	-1.183B	743.0M
Cash From Financing Activities	$661.0M	-744.0M	-917.0M
Net Change In Cash	$1.257B	-1.278B	179.0M
YoY Change	22.28%	255.99%	-68.76%
FREE CASH FLOW
Cash From Operating Activities	$1.090B	$649.0M	$353.0M
Capital Expenditures	-$86.00M	-$25.00M	-$24.00M
Free Cash Flow	$1.176B	$674.0M	$377.0M
YoY Change	-31.07%	158.24%	74.54%

Facts In Submission

Frame	Concept Type	Concept / XBRL Key	Value	Unit
CY2019	cma	Defined Benefit Plan Market Related Value Plan Assets Amortization Period DefinedBenefitPlanMarketRelatedValuePlanAssetsAmortizationPeriod	P5Y
CY2019	cma	Delinquency Status Unpaid Scheduled Monthly Payment DelinquencyStatusUnpaidScheduledMonthlyPayment	P30D
CY2017	cma	Profit Sharing Plan Costs Recognized ProfitSharingPlanCostsRecognized	1000000	USD
CY2018	cma	Profit Sharing Plan Costs Recognized ProfitSharingPlanCostsRecognized	0	USD
CY2019	cma	Profit Sharing Plan Costs Recognized ProfitSharingPlanCostsRecognized	0	USD
CY2019	dei	Amendment Flag AmendmentFlag	false
CY2019	dei	Current Fiscal Year End Date CurrentFiscalYearEndDate	--12-31
CY2019	dei	Document Fiscal Period Focus DocumentFiscalPeriodFocus	FY
CY2019	dei	Document Fiscal Year Focus DocumentFiscalYearFocus	2019
CY2019	dei	Document Transition Report DocumentTransitionReport	false
CY2019	dei	Entity Central Index Key EntityCentralIndexKey	0000028412
CY2019	dei	Entity Emerging Growth Company EntityEmergingGrowthCompany	false
CY2019	dei	Entity Shell Company EntityShellCompany	false
CY2019	dei	Entity Small Business EntitySmallBusiness	false
CY2019	us-gaap	Average Term Of Credit Risk Derivatives1 AverageTermOfCreditRiskDerivatives1	P3Y4M24D
CY2018Q4	us-gaap	Common Stock Par Or Stated Value Per Share CommonStockParOrStatedValuePerShare	5
CY2018Q4	us-gaap	Common Stock Shares Authorized CommonStockSharesAuthorized	325000000	shares
CY2019Q4	us-gaap	Common Stock Shares Authorized CommonStockSharesAuthorized	325000000	shares
CY2018Q4	us-gaap	Capital Required To Be Well Capitalized To Risk Weighted Assets CapitalRequiredToBeWellCapitalizedToRiskWeightedAssets	0.10
CY2018Q4	us-gaap	Common Stock Shares Issued CommonStockSharesIssued	228164824	shares
CY2019Q4	us-gaap	Common Stock Shares Issued CommonStockSharesIssued	228164824	shares
CY2017	us-gaap	Defined Contribution Plan Cost Recognized DefinedContributionPlanCostRecognized	21000000	USD
CY2018	us-gaap	Defined Contribution Plan Cost Recognized DefinedContributionPlanCostRecognized	21000000	USD
CY2019Q4	us-gaap	Derivative Liability Fair Value Of Collateral DerivativeLiabilityFairValueOfCollateral	0	USD
CY2019	us-gaap	Employee Service Share Based Compensation Nonvested Awards Total Compensation Cost Not Yet Recognized Period For Recognition1 EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1	P2Y3M7D
CY2018Q4	us-gaap	Federal Home Loan Bank Stock FederalHomeLoanBankStock	163000000	USD
CY2018Q4	us-gaap	Federal Reserve Bank Stock FederalReserveBankStock	85000000	USD
CY2019	us-gaap	Gain Loss On Foreign Currency Derivative Instruments Not Designated As Hedging Instruments GainLossOnForeignCurrencyDerivativeInstrumentsNotDesignatedAsHedgingInstruments	0	USD
CY2019Q4	us-gaap	Lessee Operating Lease Term Of Contract LesseeOperatingLeaseTermOfContract	P9Y0M0D
CY2018Q4	us-gaap	Letters Of Credit Outstanding Amount LettersOfCreditOutstandingAmount	3300000000	USD
CY2017	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Fair Value Assumptions Expected Term1 SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1	P6Y10M24D
CY2018	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Fair Value Assumptions Expected Term1 SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1	P7Y4M24D
CY2019	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Fair Value Assumptions Expected Term1 SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1	P7Y7M6D
CY2018Q4	us-gaap	Tier One Risk Based Capital Required To Be Well Capitalized To Risk Weighted Assets TierOneRiskBasedCapitalRequiredToBeWellCapitalizedToRiskWeightedAssets	0.06
CY2018Q4	us-gaap	Treasury Stock Shares TreasuryStockShares	68081176	shares
CY2019Q4	us-gaap	Treasury Stock Shares TreasuryStockShares	86069234	shares
CY2017	us-gaap	Variable Interest Entity Financial Or Other Support Amount VariableInterestEntityFinancialOrOtherSupportAmount	0	USD
CY2018	us-gaap	Variable Interest Entity Financial Or Other Support Amount VariableInterestEntityFinancialOrOtherSupportAmount	0	USD
CY2019	dei	Document Type DocumentType	10-K
CY2019	dei	Document Annual Report DocumentAnnualReport	true
CY2019	dei	Document Period End Date DocumentPeriodEndDate	2019-12-31
CY2019	dei	Document Transition Report DocumentTransitionReport	false
CY2019	dei	Entity File Number EntityFileNumber	1-10706
CY2019	dei	Entity Registrant Name EntityRegistrantName	Comerica Incorporated
CY2019	dei	Entity Incorporation State Country Code EntityIncorporationStateCountryCode	DE
CY2019	dei	Entity Tax Identification Number EntityTaxIdentificationNumber	38-1998421
CY2019	dei	Entity Address Address Line1 EntityAddressAddressLine1	1717 Main Street, MC 6404
CY2019	dei	Entity Address City Or Town EntityAddressCityOrTown	Dallas
CY2019	dei	Entity Address State Or Province EntityAddressStateOrProvince	TX
CY2019	dei	Entity Address Postal Zip Code EntityAddressPostalZipCode	75201
CY2019	dei	City Area Code CityAreaCode	(214)
CY2019	dei	Local Phone Number LocalPhoneNumber	462-6831
CY2019	dei	Security12b Title Security12bTitle	Common Stock, $5 par value
CY2019	dei	Trading Symbol TradingSymbol	CMA
CY2019	dei	Security Exchange Name SecurityExchangeName	NYSE
CY2019	dei	Entity Well Known Seasoned Issuer EntityWellKnownSeasonedIssuer	Yes
CY2019	dei	Entity Voluntary Filers EntityVoluntaryFilers	No
CY2019	dei	Entity Current Reporting Status EntityCurrentReportingStatus	Yes
CY2019	dei	Entity Interactive Data Current EntityInteractiveDataCurrent	Yes
CY2019	dei	Entity Filer Category EntityFilerCategory	Large Accelerated Filer
CY2019	dei	Entity Small Business EntitySmallBusiness	false
CY2019	dei	Entity Emerging Growth Company EntityEmergingGrowthCompany	false
CY2019	dei	Entity Shell Company EntityShellCompany	false
CY2019Q2	dei	Entity Public Float EntityPublicFloat	10700000000	USD
CY2020Q1	dei	Entity Common Stock Shares Outstanding EntityCommonStockSharesOutstanding	141346049	shares
CY2019Q4	us-gaap	Common Stock Par Or Stated Value Per Share CommonStockParOrStatedValuePerShare	5
CY2019Q4	us-gaap	Cash And Due From Banks CashAndDueFromBanks	973000000	USD
CY2018Q4	us-gaap	Cash And Due From Banks CashAndDueFromBanks	1390000000	USD
CY2019Q4	us-gaap	Interest Bearing Deposits In Banks InterestBearingDepositsInBanks	4845000000	USD
CY2018Q4	us-gaap	Interest Bearing Deposits In Banks InterestBearingDepositsInBanks	3171000000	USD
CY2019Q4	us-gaap	Other Short Term Investments OtherShortTermInvestments	155000000	USD
CY2018Q4	us-gaap	Other Short Term Investments OtherShortTermInvestments	134000000	USD
CY2019Q4	us-gaap	Available For Sale Securities AvailableForSaleSecurities	12398000000	USD
CY2018Q4	us-gaap	Available For Sale Securities AvailableForSaleSecurities	12045000000	USD
CY2019Q4	cma	Loans Receivable Commercial Financial And Agricultural Net Of Deferred Income LoansReceivableCommercialFinancialAndAgriculturalNetOfDeferredIncome	31473000000	USD
CY2018Q4	cma	Loans Receivable Commercial Financial And Agricultural Net Of Deferred Income LoansReceivableCommercialFinancialAndAgriculturalNetOfDeferredIncome	31976000000	USD
CY2019Q4	cma	Real Estate Construction Loans Net Of Deferred Income RealEstateConstructionLoansNetOfDeferredIncome	3455000000	USD
CY2018Q4	cma	Real Estate Construction Loans Net Of Deferred Income RealEstateConstructionLoansNetOfDeferredIncome	3077000000	USD
CY2019Q4	cma	Loans Receivable Commercial Mortgage Net Of Deferred Income LoansReceivableCommercialMortgageNetOfDeferredIncome	9559000000	USD
CY2018Q4	cma	Loans Receivable Commercial Mortgage Net Of Deferred Income LoansReceivableCommercialMortgageNetOfDeferredIncome	9106000000	USD
CY2019Q4	cma	Leases Receivable Commercial Lease Financing Net Of Deferred Income LeasesReceivableCommercialLeaseFinancingNetOfDeferredIncome	588000000	USD
CY2018Q4	cma	Leases Receivable Commercial Lease Financing Net Of Deferred Income LeasesReceivableCommercialLeaseFinancingNetOfDeferredIncome	507000000	USD
CY2019Q4	cma	Loans And Leases Receivable Foreign Net Of Deferred Income Other LoansAndLeasesReceivableForeignNetOfDeferredIncomeOther	1009000000	USD
CY2018Q4	cma	Loans And Leases Receivable Foreign Net Of Deferred Income Other LoansAndLeasesReceivableForeignNetOfDeferredIncomeOther	1013000000	USD
CY2019Q4	cma	Loans And Leases Receivable Consumer Mortgage Net Of Deferred Income LoansAndLeasesReceivableConsumerMortgageNetOfDeferredIncome	1845000000	USD
CY2018Q4	cma	Loans And Leases Receivable Consumer Mortgage Net Of Deferred Income LoansAndLeasesReceivableConsumerMortgageNetOfDeferredIncome	1970000000	USD
CY2019Q4	cma	Loans And Leases Receivable Consumer Loans Net Of Deferred Income LoansAndLeasesReceivableConsumerLoansNetOfDeferredIncome	2440000000	USD
CY2018Q4	cma	Loans And Leases Receivable Consumer Loans Net Of Deferred Income LoansAndLeasesReceivableConsumerLoansNetOfDeferredIncome	2514000000	USD
CY2019Q4	us-gaap	Loans And Leases Receivable Net Of Deferred Income LoansAndLeasesReceivableNetOfDeferredIncome	50369000000	USD
CY2018Q4	us-gaap	Loans And Leases Receivable Net Of Deferred Income LoansAndLeasesReceivableNetOfDeferredIncome	50163000000	USD
CY2019Q4	us-gaap	Loans And Leases Receivable Allowance LoansAndLeasesReceivableAllowance	637000000	USD
CY2018Q4	us-gaap	Loans And Leases Receivable Allowance LoansAndLeasesReceivableAllowance	671000000	USD
CY2019Q4	us-gaap	Loans And Leases Receivable Net Reported Amount LoansAndLeasesReceivableNetReportedAmount	49732000000	USD
CY2018Q4	us-gaap	Loans And Leases Receivable Net Reported Amount LoansAndLeasesReceivableNetReportedAmount	49492000000	USD
CY2019Q4	us-gaap	Property Plant And Equipment Net PropertyPlantAndEquipmentNet	457000000	USD
CY2018Q4	us-gaap	Property Plant And Equipment Net PropertyPlantAndEquipmentNet	475000000	USD
CY2019Q4	us-gaap	Other Assets OtherAssets	4842000000	USD
CY2018Q4	us-gaap	Other Assets OtherAssets	4111000000	USD
CY2018Q4	us-gaap	Deposits Money Market Deposits And Negotiable Order Of Withdrawal Now DepositsMoneyMarketDepositsAndNegotiableOrderOfWithdrawalNOW	22560000000	USD
CY2019Q4	us-gaap	Assets Assets	73402000000	USD
CY2018Q4	us-gaap	Assets Assets	70818000000	USD
CY2019Q4	us-gaap	Noninterest Bearing Deposit Liabilities NoninterestBearingDepositLiabilities	27382000000	USD
CY2018Q4	us-gaap	Noninterest Bearing Deposit Liabilities NoninterestBearingDepositLiabilities	28690000000	USD
CY2019Q4	us-gaap	Deposits Money Market Deposits And Negotiable Order Of Withdrawal Now DepositsMoneyMarketDepositsAndNegotiableOrderOfWithdrawalNOW	24527000000	USD
CY2019Q4	us-gaap	Deposits Savings Deposits DepositsSavingsDeposits	2184000000	USD
CY2018Q4	us-gaap	Deposits Savings Deposits DepositsSavingsDeposits	2172000000	USD
CY2019Q4	cma	Deposits Customer Certificates Deposits DepositsCustomerCertificatesDeposits	2978000000	USD
CY2018Q4	cma	Deposits Customer Certificates Deposits DepositsCustomerCertificatesDeposits	2131000000	USD
CY2019Q4	cma	Other Time Deposits OtherTimeDeposits	133000000	USD
CY2018Q4	cma	Other Time Deposits OtherTimeDeposits	0	USD
CY2019Q4	us-gaap	Interest Bearing Foreign Deposit Time Deposits InterestBearingForeignDepositTimeDeposits	91000000	USD
CY2018Q4	us-gaap	Interest Bearing Foreign Deposit Time Deposits InterestBearingForeignDepositTimeDeposits	8000000	USD
CY2019Q4	us-gaap	Interest Bearing Deposit Liabilities InterestBearingDepositLiabilities	29913000000	USD
CY2018Q4	us-gaap	Interest Bearing Deposit Liabilities InterestBearingDepositLiabilities	26871000000	USD
CY2019Q4	us-gaap	Deposits Deposits	57295000000	USD
CY2018Q4	us-gaap	Deposits Deposits	55561000000	USD
CY2019Q4	us-gaap	Short Term Borrowings ShortTermBorrowings	71000000	USD
CY2018Q4	us-gaap	Short Term Borrowings ShortTermBorrowings	44000000	USD
CY2019Q4	us-gaap	Other Liabilities OtherLiabilities	1440000000	USD
CY2018Q4	us-gaap	Other Liabilities OtherLiabilities	1243000000	USD
CY2019Q4	us-gaap	Long Term Debt LongTermDebt	7269000000	USD
CY2018Q4	us-gaap	Long Term Debt LongTermDebt	6463000000	USD
CY2019Q4	us-gaap	Liabilities Liabilities	66075000000	USD
CY2018Q4	us-gaap	Liabilities Liabilities	63311000000	USD
CY2019Q4	us-gaap	Common Stock Value CommonStockValue	1141000000	USD
CY2018Q4	us-gaap	Common Stock Value CommonStockValue	1141000000	USD
CY2019Q4	us-gaap	Additional Paid In Capital Common Stock AdditionalPaidInCapitalCommonStock	2174000000	USD
CY2018Q4	us-gaap	Additional Paid In Capital Common Stock AdditionalPaidInCapitalCommonStock	2148000000	USD
CY2019Q4	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	-235000000	USD
CY2018Q4	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	-609000000	USD
CY2019Q4	us-gaap	Retained Earnings Accumulated Deficit RetainedEarningsAccumulatedDeficit	9538000000	USD
CY2018Q4	us-gaap	Retained Earnings Accumulated Deficit RetainedEarningsAccumulatedDeficit	8781000000	USD
CY2019Q4	us-gaap	Treasury Stock Value TreasuryStockValue	5291000000	USD
CY2018Q4	us-gaap	Treasury Stock Value TreasuryStockValue	3954000000	USD
CY2019Q4	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	7327000000	USD
CY2018Q4	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	7507000000	USD
CY2019Q4	us-gaap	Liabilities And Stockholders Equity LiabilitiesAndStockholdersEquity	73402000000	USD
CY2018Q4	us-gaap	Liabilities And Stockholders Equity LiabilitiesAndStockholdersEquity	70818000000	USD
CY2019	us-gaap	Interest And Fee Income Loans And Leases Held In Portfolio InterestAndFeeIncomeLoansAndLeasesHeldInPortfolio	2439000000	USD
CY2018	us-gaap	Interest And Fee Income Loans And Leases Held In Portfolio InterestAndFeeIncomeLoansAndLeasesHeldInPortfolio	2262000000	USD
CY2017	us-gaap	Interest And Fee Income Loans And Leases Held In Portfolio InterestAndFeeIncomeLoansAndLeasesHeldInPortfolio	1872000000	USD
CY2019	cma	Interest And Dividend Income Securities Afs And Htm InterestAndDividendIncomeSecuritiesAFSAndHTM	297000000	USD
CY2018	cma	Interest And Dividend Income Securities Afs And Htm InterestAndDividendIncomeSecuritiesAFSAndHTM	265000000	USD
CY2017	cma	Interest And Dividend Income Securities Afs And Htm InterestAndDividendIncomeSecuritiesAFSAndHTM	250000000	USD
CY2019	us-gaap	Other Interest And Dividend Income OtherInterestAndDividendIncome	71000000	USD
CY2018	us-gaap	Other Interest And Dividend Income OtherInterestAndDividendIncome	92000000	USD
CY2017	us-gaap	Other Interest And Dividend Income OtherInterestAndDividendIncome	60000000	USD
CY2019	us-gaap	Interest And Dividend Income Operating InterestAndDividendIncomeOperating	2807000000	USD
CY2018	us-gaap	Interest And Dividend Income Operating InterestAndDividendIncomeOperating	2619000000	USD
CY2017	us-gaap	Interest And Dividend Income Operating InterestAndDividendIncomeOperating	2182000000	USD
CY2019	us-gaap	Interest Expense Deposits InterestExpenseDeposits	262000000	USD
CY2018	us-gaap	Interest Expense Deposits InterestExpenseDeposits	122000000	USD
CY2017	us-gaap	Interest Expense Deposits InterestExpenseDeposits	42000000	USD
CY2019	us-gaap	Interest Expense Short Term Borrowings InterestExpenseShortTermBorrowings	9000000	USD
CY2018	us-gaap	Interest Expense Short Term Borrowings InterestExpenseShortTermBorrowings	1000000	USD
CY2017	us-gaap	Interest Expense Short Term Borrowings InterestExpenseShortTermBorrowings	3000000	USD
CY2019	us-gaap	Interest Expense Long Term Debt InterestExpenseLongTermDebt	197000000	USD
CY2018	us-gaap	Interest Expense Long Term Debt InterestExpenseLongTermDebt	144000000	USD
CY2017	us-gaap	Interest Expense Long Term Debt InterestExpenseLongTermDebt	76000000	USD
CY2019	us-gaap	Interest Expense InterestExpense	468000000	USD
CY2018	us-gaap	Interest Expense InterestExpense	267000000	USD
CY2017	us-gaap	Interest Expense InterestExpense	121000000	USD
CY2019	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	2339000000	USD
CY2018	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	2352000000	USD
CY2017	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	2061000000	USD
CY2019	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	74000000	USD
CY2018	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	-1000000	USD
CY2017	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	74000000	USD
CY2019	us-gaap	Interest Income Expense After Provision For Loan Loss InterestIncomeExpenseAfterProvisionForLoanLoss	2265000000	USD
CY2018	us-gaap	Interest Income Expense After Provision For Loan Loss InterestIncomeExpenseAfterProvisionForLoanLoss	2353000000	USD
CY2017	us-gaap	Interest Income Expense After Provision For Loan Loss InterestIncomeExpenseAfterProvisionForLoanLoss	1987000000	USD
CY2019	cma	Card Fees CardFees	257000000	USD
CY2018	cma	Card Fees CardFees	244000000	USD
CY2017	cma	Card Fees CardFees	333000000	USD
CY2019	cma	Fiduciaryincome Fiduciaryincome	206000000	USD
CY2018	cma	Fiduciaryincome Fiduciaryincome	206000000	USD
CY2017	cma	Fiduciaryincome Fiduciaryincome	198000000	USD
CY2019	cma	Servicechargesondepositaccounts Servicechargesondepositaccounts	203000000	USD
CY2018	cma	Servicechargesondepositaccounts Servicechargesondepositaccounts	211000000	USD
CY2017	cma	Servicechargesondepositaccounts Servicechargesondepositaccounts	227000000	USD
CY2019	cma	Commercial Lending Fees CommercialLendingFees	91000000	USD
CY2018	cma	Commercial Lending Fees CommercialLendingFees	85000000	USD
CY2017	cma	Commercial Lending Fees CommercialLendingFees	85000000	USD
CY2019	us-gaap	Foreign Currency Transaction Gain Loss Before Tax ForeignCurrencyTransactionGainLossBeforeTax	44000000	USD
CY2018	us-gaap	Bank Owned Life Insurance Income BankOwnedLifeInsuranceIncome	39000000	USD
CY2018	us-gaap	Foreign Currency Transaction Gain Loss Before Tax ForeignCurrencyTransactionGainLossBeforeTax	47000000	USD
CY2017	us-gaap	Foreign Currency Transaction Gain Loss Before Tax ForeignCurrencyTransactionGainLossBeforeTax	45000000	USD
CY2019	us-gaap	Bank Owned Life Insurance Income BankOwnedLifeInsuranceIncome	41000000	USD
CY2017	us-gaap	Bank Owned Life Insurance Income BankOwnedLifeInsuranceIncome	43000000	USD
CY2019	cma	Letter Of Credit Fees LetterOfCreditFees	38000000	USD
CY2018	cma	Letter Of Credit Fees LetterOfCreditFees	40000000	USD
CY2017	cma	Letter Of Credit Fees LetterOfCreditFees	45000000	USD
CY2019	us-gaap	Brokerage Commissions Revenue BrokerageCommissionsRevenue	28000000	USD
CY2018	us-gaap	Brokerage Commissions Revenue BrokerageCommissionsRevenue	27000000	USD
CY2017	us-gaap	Brokerage Commissions Revenue BrokerageCommissionsRevenue	23000000	USD
CY2019	us-gaap	Debt And Equity Securities Gain Loss DebtAndEquitySecuritiesGainLoss	-7000000	USD
CY2018	us-gaap	Debt And Equity Securities Gain Loss DebtAndEquitySecuritiesGainLoss	-19000000	USD
CY2017	us-gaap	Debt And Equity Securities Gain Loss DebtAndEquitySecuritiesGainLoss	0	USD
CY2019	us-gaap	Noninterest Income Other Operating Income NoninterestIncomeOtherOperatingIncome	109000000	USD
CY2018	us-gaap	Noninterest Income Other Operating Income NoninterestIncomeOtherOperatingIncome	96000000	USD
CY2017	us-gaap	Noninterest Income Other Operating Income NoninterestIncomeOtherOperatingIncome	108000000	USD
CY2019	us-gaap	Noninterest Income NoninterestIncome	1010000000	USD
CY2018	us-gaap	Noninterest Income NoninterestIncome	976000000	USD
CY2017	us-gaap	Noninterest Income NoninterestIncome	1107000000	USD
CY2019	us-gaap	Labor And Related Expense LaborAndRelatedExpense	1020000000	USD
CY2018	us-gaap	Labor And Related Expense LaborAndRelatedExpense	1009000000	USD
CY2017	us-gaap	Labor And Related Expense LaborAndRelatedExpense	961000000	USD
CY2019	cma	Outside Processing Fee Expense OutsideProcessingFeeExpense	264000000	USD
CY2018	cma	Outside Processing Fee Expense OutsideProcessingFeeExpense	255000000	USD
CY2017	cma	Outside Processing Fee Expense OutsideProcessingFeeExpense	366000000	USD
CY2019	us-gaap	Occupancy Net OccupancyNet	154000000	USD
CY2018	us-gaap	Occupancy Net OccupancyNet	152000000	USD
CY2017	us-gaap	Occupancy Net OccupancyNet	154000000	USD
CY2019	cma	Software Expenses SoftwareExpenses	117000000	USD
CY2018	cma	Software Expenses SoftwareExpenses	125000000	USD
CY2017	cma	Software Expenses SoftwareExpenses	126000000	USD
CY2019	us-gaap	Equipment Expense EquipmentExpense	50000000	USD
CY2018	us-gaap	Equipment Expense EquipmentExpense	48000000	USD
CY2017	us-gaap	Equipment Expense EquipmentExpense	45000000	USD
CY2019	us-gaap	Advertising Expense AdvertisingExpense	34000000	USD
CY2018	us-gaap	Advertising Expense AdvertisingExpense	30000000	USD
CY2017	us-gaap	Advertising Expense AdvertisingExpense	28000000	USD
CY2019	us-gaap	Federal Deposit Insurance Corporation Premium Expense FederalDepositInsuranceCorporationPremiumExpense	23000000	USD
CY2018	us-gaap	Federal Deposit Insurance Corporation Premium Expense FederalDepositInsuranceCorporationPremiumExpense	42000000	USD
CY2017	us-gaap	Federal Deposit Insurance Corporation Premium Expense FederalDepositInsuranceCorporationPremiumExpense	51000000	USD
CY2019	us-gaap	Restructuring Charges RestructuringCharges	0	USD
CY2018	us-gaap	Restructuring Charges RestructuringCharges	53000000	USD
CY2017	us-gaap	Restructuring Charges RestructuringCharges	45000000	USD
CY2019	us-gaap	Other Noninterest Expense OtherNoninterestExpense	81000000	USD
CY2018	us-gaap	Other Noninterest Expense OtherNoninterestExpense	80000000	USD
CY2017	us-gaap	Other Noninterest Expense OtherNoninterestExpense	84000000	USD
CY2019	us-gaap	Noninterest Expense NoninterestExpense	1743000000	USD
CY2018	us-gaap	Noninterest Expense NoninterestExpense	1794000000	USD
CY2017	us-gaap	Noninterest Expense NoninterestExpense	1860000000	USD
CY2019	cma	Income Loss From Continuing Operations Before Income Taxes IncomeLossFromContinuingOperationsBeforeIncomeTaxes	1532000000	USD
CY2018	cma	Income Loss From Continuing Operations Before Income Taxes IncomeLossFromContinuingOperationsBeforeIncomeTaxes	1535000000	USD
CY2017	cma	Income Loss From Continuing Operations Before Income Taxes IncomeLossFromContinuingOperationsBeforeIncomeTaxes	1234000000	USD
CY2019	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	334000000	USD
CY2018	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	300000000	USD
CY2017	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	491000000	USD
CY2019	us-gaap	Profit Loss ProfitLoss	1198000000	USD
CY2018	us-gaap	Profit Loss ProfitLoss	1235000000	USD
CY2017	us-gaap	Profit Loss ProfitLoss	743000000	USD
CY2019	us-gaap	Undistributed Earnings Loss Allocated To Participating Securities Diluted UndistributedEarningsLossAllocatedToParticipatingSecuritiesDiluted	7000000	USD
CY2018	us-gaap	Undistributed Earnings Loss Allocated To Participating Securities Diluted UndistributedEarningsLossAllocatedToParticipatingSecuritiesDiluted	8000000	USD
CY2017	us-gaap	Undistributed Earnings Loss Allocated To Participating Securities Diluted UndistributedEarningsLossAllocatedToParticipatingSecuritiesDiluted	5000000	USD
CY2019	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	1191000000	USD
CY2018	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	1227000000	USD
CY2017	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	738000000	USD
CY2019	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	7.95
CY2018	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	7.31
CY2017	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	4.23
CY2019	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	7.87
CY2018	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	7.20
CY2017	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	4.14
CY2019	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	398000000	USD
CY2018	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	309000000	USD
CY2017	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	193000000	USD
CY2019	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	2.68
CY2018	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	1.84
CY2017	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	1.09
CY2019	us-gaap	Profit Loss ProfitLoss	1198000000	USD
CY2018	us-gaap	Profit Loss ProfitLoss	1235000000	USD
CY2017	us-gaap	Profit Loss ProfitLoss	743000000	USD
CY2019	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Before Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodBeforeTax	257000000	USD
CY2018	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Before Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodBeforeTax	-69000000	USD
CY2017	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Before Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodBeforeTax	-81000000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesBeforeTax	-8000000	USD
CY2018	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesBeforeTax	-20000000	USD
CY2017	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesBeforeTax	0	USD
CY2019	cma	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Amortization Of Unrealized Losses On Afs Securities Transferred To Htm Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForAmortizationOfUnrealizedLossesOnAFSSecuritiesTransferredToHTMBeforeTax	0	USD
CY2018	cma	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Amortization Of Unrealized Losses On Afs Securities Transferred To Htm Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForAmortizationOfUnrealizedLossesOnAFSSecuritiesTransferredToHTMBeforeTax	0	USD
CY2017	cma	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Amortization Of Unrealized Losses On Afs Securities Transferred To Htm Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForAmortizationOfUnrealizedLossesOnAFSSecuritiesTransferredToHTMBeforeTax	-3000000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Adjustment Before Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentBeforeTax	265000000	USD
CY2018	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Adjustment Before Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentBeforeTax	-49000000	USD
CY2017	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Adjustment Before Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentBeforeTax	-78000000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Derivatives Qualifying As Hedges Before Tax OtherComprehensiveIncomeLossDerivativesQualifyingAsHedgesBeforeTax	44000000	USD
CY2018	us-gaap	Other Comprehensive Income Loss Derivatives Qualifying As Hedges Before Tax OtherComprehensiveIncomeLossDerivativesQualifyingAsHedgesBeforeTax	0	USD
CY2017	us-gaap	Other Comprehensive Income Loss Derivatives Qualifying As Hedges Before Tax OtherComprehensiveIncomeLossDerivativesQualifyingAsHedgesBeforeTax	0	USD
CY2019	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Net Unamortized Gain Loss Arising During Period Before Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansNetUnamortizedGainLossArisingDuringPeriodBeforeTax	163000000	USD
CY2018	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Net Unamortized Gain Loss Arising During Period Before Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansNetUnamortizedGainLossArisingDuringPeriodBeforeTax	-191000000	USD
CY2017	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Net Unamortized Gain Loss Arising During Period Before Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansNetUnamortizedGainLossArisingDuringPeriodBeforeTax	72000000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci Pension And Other Postretirement Benefit Plans For Net Gain Loss Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetGainLossBeforeTax	42000000	USD
CY2018	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci Pension And Other Postretirement Benefit Plans For Net Gain Loss Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetGainLossBeforeTax	61000000	USD
CY2017	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci Pension And Other Postretirement Benefit Plans For Net Gain Loss Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetGainLossBeforeTax	51000000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Amortization Adjustment From Aoci Pension And Other Postretirement Benefit Plans For Net Prior Service Cost Credit Before Tax OtherComprehensiveIncomeLossAmortizationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetPriorServiceCostCreditBeforeTax	-27000000	USD
CY2018	us-gaap	Other Comprehensive Income Loss Amortization Adjustment From Aoci Pension And Other Postretirement Benefit Plans For Net Prior Service Cost Credit Before Tax OtherComprehensiveIncomeLossAmortizationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetPriorServiceCostCreditBeforeTax	-27000000	USD
CY2017	us-gaap	Other Comprehensive Income Loss Amortization Adjustment From Aoci Pension And Other Postretirement Benefit Plans For Net Prior Service Cost Credit Before Tax OtherComprehensiveIncomeLossAmortizationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetPriorServiceCostCreditBeforeTax	-27000000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Adjustment Before Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentBeforeTax	-178000000	USD
CY2018	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Adjustment Before Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentBeforeTax	157000000	USD
CY2017	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Adjustment Before Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentBeforeTax	-96000000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Before Tax OtherComprehensiveIncomeLossBeforeTax	487000000	USD
CY2018	us-gaap	Other Comprehensive Income Loss Before Tax OtherComprehensiveIncomeLossBeforeTax	-206000000	USD
CY2017	us-gaap	Other Comprehensive Income Loss Before Tax OtherComprehensiveIncomeLossBeforeTax	18000000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Tax OtherComprehensiveIncomeLossTax	113000000	USD
CY2018	us-gaap	Other Comprehensive Income Loss Tax OtherComprehensiveIncomeLossTax	-47000000	USD
CY2017	us-gaap	Other Comprehensive Income Loss Tax OtherComprehensiveIncomeLossTax	-1000000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	374000000	USD
CY2018	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	-159000000	USD
CY2017	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	19000000	USD
CY2019	us-gaap	Comprehensive Income Net Of Tax Including Portion Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest	1572000000	USD
CY2018	us-gaap	Comprehensive Income Net Of Tax Including Portion Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest	1076000000	USD
CY2017	us-gaap	Comprehensive Income Net Of Tax Including Portion Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest	762000000	USD
CY2016Q4	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	7796000000	USD
CY2016Q4	us-gaap	New Accounting Pronouncement Or Change In Accounting Principle Cumulative Effect Of Change On Equity Or Net Assets1 NewAccountingPronouncementOrChangeInAccountingPrincipleCumulativeEffectOfChangeOnEquityOrNetAssets1	1000000	USD
CY2017	us-gaap	Profit Loss ProfitLoss	743000000	USD
CY2017	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	19000000	USD
CY2017	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	193000000	USD
CY2017	us-gaap	Treasury Stock Value Acquired Cost Method TreasuryStockValueAcquiredCostMethod	544000000	USD
CY2017	us-gaap	Stock Issued During Period Value Share Based Compensation StockIssuedDuringPeriodValueShareBasedCompensation	102000000	USD
CY2017	cma	Stock Issued During Period Value Warrants Exercised StockIssuedDuringPeriodValueWarrantsExercised	0	USD
CY2017	us-gaap	Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	39000000	USD
CY2017	cma	Reclassificationof Certain Tax Effectsfrom Accumulated Other Comprehensive Income Total ReclassificationofCertainTaxEffectsfromAccumulatedOtherComprehensiveIncomeTotal	0	USD
CY2017	us-gaap	Stockholders Equity Other StockholdersEquityOther	0	USD
CY2017Q4	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	7963000000	USD
CY2017Q4	us-gaap	New Accounting Pronouncement Or Change In Accounting Principle Cumulative Effect Of Change On Equity Or Net Assets1 NewAccountingPronouncementOrChangeInAccountingPrincipleCumulativeEffectOfChangeOnEquityOrNetAssets1	15000000	USD
CY2018	us-gaap	Profit Loss ProfitLoss	1235000000	USD
CY2018	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	-159000000	USD
CY2018	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	309000000	USD
CY2018	us-gaap	Treasury Stock Value Acquired Cost Method TreasuryStockValueAcquiredCostMethod	1329000000	USD
CY2018	us-gaap	Stock Issued During Period Value Share Based Compensation StockIssuedDuringPeriodValueShareBasedCompensation	43000000	USD
CY2018	cma	Stock Issued During Period Value Warrants Exercised StockIssuedDuringPeriodValueWarrantsExercised	0	USD
CY2018	us-gaap	Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	48000000	USD
CY2018Q4	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	7507000000	USD
CY2018Q4	us-gaap	New Accounting Pronouncement Or Change In Accounting Principle Cumulative Effect Of Change On Equity Or Net Assets1 NewAccountingPronouncementOrChangeInAccountingPrincipleCumulativeEffectOfChangeOnEquityOrNetAssets1	-14000000	USD
CY2019	us-gaap	Profit Loss ProfitLoss	1198000000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	374000000	USD
CY2019	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	398000000	USD
CY2019	us-gaap	Treasury Stock Value Acquired Cost Method TreasuryStockValueAcquiredCostMethod	1380000000	USD
CY2019	us-gaap	Stock Issued During Period Value Share Based Compensation StockIssuedDuringPeriodValueShareBasedCompensation	1000000	USD
CY2019	us-gaap	Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	39000000	USD
CY2019Q4	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	7327000000	USD
CY2019	us-gaap	Profit Loss ProfitLoss	1198000000	USD
CY2018	us-gaap	Profit Loss ProfitLoss	1235000000	USD
CY2017	us-gaap	Profit Loss ProfitLoss	743000000	USD
CY2019	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	74000000	USD
CY2018	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	-1000000	USD
CY2017	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	74000000	USD
CY2019	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	12000000	USD
CY2018	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	24000000	USD
CY2017	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	79000000	USD
CY2019	us-gaap	Depreciation And Amortization DepreciationAndAmortization	114000000	USD
CY2018	us-gaap	Depreciation And Amortization DepreciationAndAmortization	120000000	USD
CY2017	us-gaap	Depreciation And Amortization DepreciationAndAmortization	121000000	USD
CY2019	us-gaap	Defined Benefit Plan Net Periodic Benefit Cost DefinedBenefitPlanNetPeriodicBenefitCost	-29000000	USD
CY2018	us-gaap	Defined Benefit Plan Net Periodic Benefit Cost DefinedBenefitPlanNetPeriodicBenefitCost	-18000000	USD
CY2017	us-gaap	Defined Benefit Plan Net Periodic Benefit Cost DefinedBenefitPlanNetPeriodicBenefitCost	-18000000	USD
CY2019	us-gaap	Share Based Compensation ShareBasedCompensation	39000000	USD
CY2018	us-gaap	Share Based Compensation ShareBasedCompensation	48000000	USD
CY2017	us-gaap	Share Based Compensation ShareBasedCompensation	39000000	USD
CY2019	us-gaap	Accretion Amortization Of Discounts And Premiums Investments AccretionAmortizationOfDiscountsAndPremiumsInvestments	-2000000	USD
CY2018	us-gaap	Accretion Amortization Of Discounts And Premiums Investments AccretionAmortizationOfDiscountsAndPremiumsInvestments	-3000000	USD
CY2017	us-gaap	Accretion Amortization Of Discounts And Premiums Investments AccretionAmortizationOfDiscountsAndPremiumsInvestments	-6000000	USD
CY2019	cma	Accretion Of Discount On Receivables Acquired In Transfer AccretionOfDiscountOnReceivablesAcquiredInTransfer	0	USD
CY2018	cma	Accretion Of Discount On Receivables Acquired In Transfer AccretionOfDiscountOnReceivablesAcquiredInTransfer	1000000	USD
CY2017	cma	Accretion Of Discount On Receivables Acquired In Transfer AccretionOfDiscountOnReceivablesAcquiredInTransfer	3000000	USD
CY2019	cma	Gain Losson Saleof Securities Net Excluding Derivative GainLossonSaleofSecuritiesNetExcludingDerivative	7000000	USD
CY2018	cma	Gain Losson Saleof Securities Net Excluding Derivative GainLossonSaleofSecuritiesNetExcludingDerivative	19000000	USD
CY2017	cma	Gain Losson Saleof Securities Net Excluding Derivative GainLossonSaleofSecuritiesNetExcludingDerivative	0	USD
CY2019	us-gaap	Gain Loss On Sale Of Other Assets GainLossOnSaleOfOtherAssets	-1000000	USD
CY2018	us-gaap	Gain Loss On Sale Of Other Assets GainLossOnSaleOfOtherAssets	1000000	USD
CY2017	us-gaap	Gain Loss On Sale Of Other Assets GainLossOnSaleOfOtherAssets	3000000	USD
CY2019	us-gaap	Increase Decrease In Other Operating Assets IncreaseDecreaseInOtherOperatingAssets	-17000000	USD
CY2018	us-gaap	Increase Decrease In Other Operating Assets IncreaseDecreaseInOtherOperatingAssets	45000000	USD
CY2017	us-gaap	Increase Decrease In Other Operating Assets IncreaseDecreaseInOtherOperatingAssets	33000000	USD
CY2019	us-gaap	Increase Decrease In Accrued Liabilities IncreaseDecreaseInAccruedLiabilities	-27000000	USD
CY2018	us-gaap	Increase Decrease In Accrued Liabilities IncreaseDecreaseInAccruedLiabilities	49000000	USD
CY2017	us-gaap	Increase Decrease In Accrued Liabilities IncreaseDecreaseInAccruedLiabilities	41000000	USD
CY2019	us-gaap	Increase Decrease In Other Operating Capital Net IncreaseDecreaseInOtherOperatingCapitalNet	318000000	USD
CY2018	us-gaap	Increase Decrease In Other Operating Capital Net IncreaseDecreaseInOtherOperatingCapitalNet	-184000000	USD
CY2017	us-gaap	Increase Decrease In Other Operating Capital Net IncreaseDecreaseInOtherOperatingCapitalNet	-39000000	USD
CY2019	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	1090000000	USD
CY2018	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	1616000000	USD
CY2017	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	1085000000	USD
CY2019	us-gaap	Proceeds From Maturities Prepayments And Calls Of Available For Sale Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities	2262000000	USD
CY2018	us-gaap	Proceeds From Maturities Prepayments And Calls Of Available For Sale Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities	1781000000	USD
CY2017	us-gaap	Proceeds From Maturities Prepayments And Calls Of Available For Sale Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities	1615000000	USD
CY2019	us-gaap	Proceeds From Sale Of Available For Sale Securities ProceedsFromSaleOfAvailableForSaleSecurities	987000000	USD
CY2018	us-gaap	Proceeds From Sale Of Available For Sale Securities ProceedsFromSaleOfAvailableForSaleSecurities	1256000000	USD
CY2017	us-gaap	Proceeds From Sale Of Available For Sale Securities ProceedsFromSaleOfAvailableForSaleSecurities	1259000000	USD
CY2019	us-gaap	Payments To Acquire Available For Sale Securities PaymentsToAcquireAvailableForSaleSecurities	3346000000	USD
CY2018	us-gaap	Payments To Acquire Available For Sale Securities PaymentsToAcquireAvailableForSaleSecurities	3032000000	USD
CY2017	us-gaap	Payments To Acquire Available For Sale Securities PaymentsToAcquireAvailableForSaleSecurities	3112000000	USD
CY2019	us-gaap	Proceeds From Maturities Prepayments And Calls Of Held To Maturity Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfHeldToMaturitySecurities	0	USD
CY2018	us-gaap	Proceeds From Maturities Prepayments And Calls Of Held To Maturity Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfHeldToMaturitySecurities	0	USD
CY2017	us-gaap	Proceeds From Maturities Prepayments And Calls Of Held To Maturity Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfHeldToMaturitySecurities	319000000	USD
CY2019	us-gaap	Payments For Proceeds From Loans And Leases PaymentsForProceedsFromLoansAndLeases	324000000	USD
CY2018	us-gaap	Payments For Proceeds From Loans And Leases PaymentsForProceedsFromLoansAndLeases	1045000000	USD
CY2017	us-gaap	Payments For Proceeds From Loans And Leases PaymentsForProceedsFromLoansAndLeases	175000000	USD
CY2019	us-gaap	Proceeds From Sale Of Foreclosed Assets ProceedsFromSaleOfForeclosedAssets	1000000	USD
CY2018	us-gaap	Proceeds From Sale Of Foreclosed Assets ProceedsFromSaleOfForeclosedAssets	8000000	USD
CY2017	us-gaap	Proceeds From Sale Of Foreclosed Assets ProceedsFromSaleOfForeclosedAssets	22000000	USD
CY2019	cma	Net Increase In Fixed Assets NetIncreaseInFixedAssets	86000000	USD
CY2018	cma	Net Increase In Fixed Assets NetIncreaseInFixedAssets	90000000	USD
CY2017	cma	Net Increase In Fixed Assets NetIncreaseInFixedAssets	69000000	USD
CY2019	us-gaap	Payments To Acquire Federal Home Loan Bank Stock PaymentsToAcquireFederalHomeLoanBankStock	201000000	USD
CY2018	us-gaap	Payments To Acquire Federal Home Loan Bank Stock PaymentsToAcquireFederalHomeLoanBankStock	41000000	USD
CY2017	us-gaap	Payments To Acquire Federal Home Loan Bank Stock PaymentsToAcquireFederalHomeLoanBankStock	42000000	USD
CY2019	us-gaap	Proceeds From Sale Of Federal Home Loan Bank Stock ProceedsFromSaleOfFederalHomeLoanBankStock	201000000	USD
CY2018	us-gaap	Proceeds From Sale Of Federal Home Loan Bank Stock ProceedsFromSaleOfFederalHomeLoanBankStock	0	USD
CY2017	us-gaap	Proceeds From Sale Of Federal Home Loan Bank Stock ProceedsFromSaleOfFederalHomeLoanBankStock	42000000	USD
CY2019	us-gaap	Proceeds From Life Insurance Policies ProceedsFromLifeInsurancePolicies	10000000	USD
CY2018	us-gaap	Proceeds From Life Insurance Policies ProceedsFromLifeInsurancePolicies	9000000	USD
CY2017	us-gaap	Proceeds From Life Insurance Policies ProceedsFromLifeInsurancePolicies	18000000	USD
CY2019	us-gaap	Payments For Proceeds From Other Investing Activities PaymentsForProceedsFromOtherInvestingActivities	-2000000	USD
CY2018	us-gaap	Payments For Proceeds From Other Investing Activities PaymentsForProceedsFromOtherInvestingActivities	2000000	USD
CY2017	us-gaap	Payments For Proceeds From Other Investing Activities PaymentsForProceedsFromOtherInvestingActivities	-3000000	USD
CY2019	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-494000000	USD
CY2018	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-1156000000	USD
CY2017	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-120000000	USD
CY2019	us-gaap	Increase Decrease In Deposits IncreaseDecreaseInDeposits	1711000000	USD
CY2018	us-gaap	Increase Decrease In Deposits IncreaseDecreaseInDeposits	-2082000000	USD
CY2017	us-gaap	Increase Decrease In Deposits IncreaseDecreaseInDeposits	-1180000000	USD
CY2019	us-gaap	Proceeds From Repayments Of Short Term Debt ProceedsFromRepaymentsOfShortTermDebt	27000000	USD
CY2018	us-gaap	Proceeds From Repayments Of Short Term Debt ProceedsFromRepaymentsOfShortTermDebt	34000000	USD
CY2017	us-gaap	Proceeds From Repayments Of Short Term Debt ProceedsFromRepaymentsOfShortTermDebt	-15000000	USD
CY2019	us-gaap	Repayments Of Long Term Debt RepaymentsOfLongTermDebt	350000000	USD
CY2018	us-gaap	Repayments Of Long Term Debt RepaymentsOfLongTermDebt	0	USD
CY2017	us-gaap	Repayments Of Long Term Debt RepaymentsOfLongTermDebt	500000000	USD
CY2019	us-gaap	Proceeds From Issuance Of Long Term Debt ProceedsFromIssuanceOfLongTermDebt	1050000000	USD
CY2018	us-gaap	Proceeds From Issuance Of Long Term Debt ProceedsFromIssuanceOfLongTermDebt	1850000000	USD
CY2017	us-gaap	Proceeds From Issuance Of Long Term Debt ProceedsFromIssuanceOfLongTermDebt	0	USD
CY2019	us-gaap	Repayments Of Other Debt RepaymentsOfOtherDebt	0	USD
CY2018	us-gaap	Repayments Of Other Debt RepaymentsOfOtherDebt	0	USD
CY2017	us-gaap	Repayments Of Other Debt RepaymentsOfOtherDebt	16000000	USD
CY2019	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	1394000000	USD
CY2018	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	1338000000	USD
CY2017	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	560000000	USD
CY2019	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	402000000	USD
CY2018	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	263000000	USD
CY2017	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	180000000	USD
CY2019	us-gaap	Proceeds From Issuance Of Shares Under Incentive And Share Based Compensation Plans Including Stock Options ProceedsFromIssuanceOfSharesUnderIncentiveAndShareBasedCompensationPlansIncludingStockOptions	18000000	USD
CY2018	us-gaap	Proceeds From Issuance Of Shares Under Incentive And Share Based Compensation Plans Including Stock Options ProceedsFromIssuanceOfSharesUnderIncentiveAndShareBasedCompensationPlansIncludingStockOptions	52000000	USD
CY2017	us-gaap	Proceeds From Issuance Of Shares Under Incentive And Share Based Compensation Plans Including Stock Options ProceedsFromIssuanceOfSharesUnderIncentiveAndShareBasedCompensationPlansIncludingStockOptions	118000000	USD
CY2019	us-gaap	Proceeds From Payments For Other Financing Activities ProceedsFromPaymentsForOtherFinancingActivities	1000000	USD
CY2018	us-gaap	Proceeds From Payments For Other Financing Activities ProceedsFromPaymentsForOtherFinancingActivities	3000000	USD
CY2017	us-gaap	Proceeds From Payments For Other Financing Activities ProceedsFromPaymentsForOtherFinancingActivities	-5000000	USD
CY2019	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	661000000	USD
CY2018	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	-1744000000	USD
CY2017	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	-2338000000	USD
CY2019	us-gaap	Cash And Cash Equivalents Period Increase Decrease CashAndCashEquivalentsPeriodIncreaseDecrease	1257000000	USD
CY2018	us-gaap	Cash And Cash Equivalents Period Increase Decrease CashAndCashEquivalentsPeriodIncreaseDecrease	-1284000000	USD
CY2017	us-gaap	Cash And Cash Equivalents Period Increase Decrease CashAndCashEquivalentsPeriodIncreaseDecrease	-1373000000	USD
CY2018Q4	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	4561000000	USD
CY2017Q4	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	5845000000	USD
CY2016Q4	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	7218000000	USD
CY2019Q4	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	5818000000	USD
CY2018Q4	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	4561000000	USD
CY2017Q4	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	5845000000	USD
CY2019	us-gaap	Interest Paid InterestPaid	462000000	USD
CY2018	us-gaap	Interest Paid InterestPaid	261000000	USD
CY2017	us-gaap	Interest Paid InterestPaid	122000000	USD
CY2019	us-gaap	Income Taxes Paid Net IncomeTaxesPaidNet	266000000	USD
CY2018	us-gaap	Income Taxes Paid Net IncomeTaxesPaidNet	200000000	USD
CY2017	us-gaap	Income Taxes Paid Net IncomeTaxesPaidNet	336000000	USD
CY2019	us-gaap	Transfer To Other Real Estate TransferToOtherRealEstate	12000000	USD
CY2018	us-gaap	Transfer To Other Real Estate TransferToOtherRealEstate	3000000	USD
CY2017	us-gaap	Transfer To Other Real Estate TransferToOtherRealEstate	8000000	USD
CY2019	us-gaap	Debt Securities Held To Maturity Transfer Amount DebtSecuritiesHeldToMaturityTransferAmount	0	USD
CY2018	us-gaap	Debt Securities Held To Maturity Transfer Amount DebtSecuritiesHeldToMaturityTransferAmount	1266000000	USD
CY2017	us-gaap	Debt Securities Held To Maturity Transfer Amount DebtSecuritiesHeldToMaturityTransferAmount	0	USD
CY2019	cma	Transfer Of Available For Sale Securities To Held To Maturity Securities TransferOfAvailableForSaleSecuritiesToHeldToMaturitySecurities	0	USD
CY2018	cma	Transfer Of Available For Sale Securities To Held To Maturity Securities TransferOfAvailableForSaleSecuritiesToHeldToMaturitySecurities	81000000	USD
CY2017	cma	Transfer Of Available For Sale Securities To Held To Maturity Securities TransferOfAvailableForSaleSecuritiesToHeldToMaturitySecurities	0	USD
CY2019	cma	Number Of Geographic Markets NumberOfGeographicMarkets	3	markets
CY2019Q4	us-gaap	Fair Value Investments Entities That Calculate Net Asset Value Per Share Unfunded Committments FairValueInvestmentsEntitiesThatCalculateNetAssetValuePerShareUnfundedCommittments	1000000	USD
CY2019Q4	us-gaap	Federal Home Loan Bank Stock FederalHomeLoanBankStock	163000000	USD
CY2019Q4	us-gaap	Federal Reserve Bank Stock FederalReserveBankStock	85000000	USD
CY2019Q4	us-gaap	Loans And Leases Receivable Deferred Income LoansAndLeasesReceivableDeferredIncome	103000000	USD
CY2018Q4	us-gaap	Loans And Leases Receivable Deferred Income LoansAndLeasesReceivableDeferredIncome	115000000	USD
CY2019Q4	cma	Allowance For Credit Losses Threshold For Individual Evaluation Nonaccrual Loans AllowanceForCreditLossesThresholdForIndividualEvaluationNonaccrualLoans	2000000	USD
CY2019Q4	cma	Allowancefor Creditlosses Thresholdfor Individual Evaluation Tdr AllowanceforCreditlossesThresholdforIndividualEvaluationTDR	1000000	USD
CY2019	us-gaap	Number Of Reporting Units NumberOfReportingUnits	3
CY2019	us-gaap	Guarantees Indemnifications And Warranties Policies GuaranteesIndemnificationsAndWarrantiesPolicies	<div style="line-height:120%;padding-top:8px;text-align:justify;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;font-weight:bold;">Financial Guarantees</span></div><div style="line-height:120%;padding-top:8px;text-align:justify;text-indent:49px;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;">Certain guarantee contracts or indemnification agreements that contingently require the Corporation, as guarantor, to make payments to the guaranteed party are initially measured at fair value and included in accrued expenses and other liabilities on the Consolidated Balance Sheets. The subsequent accounting for the liability depends on the nature of the underlying guarantee. The release from risk is accounted for under a particular guarantee when the guarantee expires or is settled, or by a systematic and rational amortization method.</span></div><div style="line-height:120%;padding-top:8px;text-align:justify;text-indent:49px;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;">Further information on the Corporation’s obligations under guarantees is included in Note </span><span style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;">8</span><span style="font-family:inherit;font-size:10pt;">.</span></div>
CY2019	cma	Defined Benefit Plan Investment Gain Loss Amortization Adjustment Allowable Percentage DefinedBenefitPlanInvestmentGainLossAmortizationAdjustmentAllowablePercentage	0.10
CY2019	cma	Defined Benefit Plan Actuarial Gain Loss Amortization Adjustment Allowable Percentage DefinedBenefitPlanActuarialGainLossAmortizationAdjustmentAllowablePercentage	0.10
CY2019Q4	cma	Overallallowanceforcreditlosses Overallallowanceforcreditlosses	668000000	USD
CY2019Q4	cma	Businessloanspercentofportfolio Businessloanspercentofportfolio	0.91
CY2019Q4	us-gaap	Available For Sale Securities Amortized Cost AvailableForSaleSecuritiesAmortizedCost	12313000000	USD
CY2019Q4	us-gaap	Available For Sale Securities Accumulated Gross Unrealized Gain Before Tax AvailableForSaleSecuritiesAccumulatedGrossUnrealizedGainBeforeTax	113000000	USD
CY2019Q4	us-gaap	Available For Sale Securities Accumulated Gross Unrealized Loss Before Tax AvailableForSaleSecuritiesAccumulatedGrossUnrealizedLossBeforeTax	28000000	USD
CY2019Q4	us-gaap	Available For Sale Securities AvailableForSaleSecurities	12398000000	USD
CY2018Q4	us-gaap	Available For Sale Securities Amortized Cost AvailableForSaleSecuritiesAmortizedCost	12225000000	USD
CY2018Q4	us-gaap	Available For Sale Securities Accumulated Gross Unrealized Gain Before Tax AvailableForSaleSecuritiesAccumulatedGrossUnrealizedGainBeforeTax	36000000	USD
CY2018Q4	us-gaap	Available For Sale Securities Accumulated Gross Unrealized Loss Before Tax AvailableForSaleSecuritiesAccumulatedGrossUnrealizedLossBeforeTax	216000000	USD
CY2018Q4	us-gaap	Available For Sale Securities AvailableForSaleSecurities	12045000000	USD
CY2019Q4	us-gaap	Available For Sale Securities Continuous Unrealized Loss Position Less Than Twelve Months Fair Value AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue	1494000000	USD
CY2019Q4	us-gaap	Available For Sale Securities Continuous Unrealized Loss Position Less Than12 Months Accumulated Loss AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss	7000000	USD
CY2019Q4	us-gaap	Available For Sale Securities Continuous Unrealized Loss Position Twelve Months Or Longer Fair Value AvailableForSaleSecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValue	1906000000	USD
CY2019Q4	us-gaap	Available For Sale Securities Continuous Unrealized Loss Position12 Months Or Longer Accumulated Loss AvailableForSaleSecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss	21000000	USD
CY2019Q4	us-gaap	Available For Sale Securities Continuous Unrealized Loss Position Fair Value AvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValue	3400000000	USD
CY2019Q4	us-gaap	Available For Sale Securities Continuous Unrealized Loss Position Accumulated Loss AvailableForSaleSecuritiesContinuousUnrealizedLossPositionAccumulatedLoss	28000000	USD
CY2018Q4	us-gaap	Available For Sale Securities Continuous Unrealized Loss Position Less Than Twelve Months Fair Value AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue	1008000000	USD
CY2018Q4	us-gaap	Available For Sale Securities Continuous Unrealized Loss Position Less Than12 Months Accumulated Loss AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss	9000000	USD
CY2018Q4	us-gaap	Available For Sale Securities Continuous Unrealized Loss Position Twelve Months Or Longer Fair Value AvailableForSaleSecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValue	7869000000	USD
CY2018Q4	us-gaap	Available For Sale Securities Continuous Unrealized Loss Position12 Months Or Longer Accumulated Loss AvailableForSaleSecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss	207000000	USD
CY2018Q4	us-gaap	Available For Sale Securities Continuous Unrealized Loss Position Fair Value AvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValue	8877000000	USD
CY2018Q4	us-gaap	Available For Sale Securities Continuous Unrealized Loss Position Accumulated Loss AvailableForSaleSecuritiesContinuousUnrealizedLossPositionAccumulatedLoss	216000000	USD
CY2019Q4	us-gaap	Availableforsale Securities In Unrealized Loss Positions Qualitative Disclosure Number Of Positions1 AvailableforsaleSecuritiesInUnrealizedLossPositionsQualitativeDisclosureNumberOfPositions1	170
CY2019	cma	Repositioningloweryieldingtreasurysecurities Repositioningloweryieldingtreasurysecurities	1000000000.0	USD
CY2018	cma	Repositioningloweryieldingtreasurysecurities Repositioningloweryieldingtreasurysecurities	1300000000	USD
CY2017	us-gaap	Debt And Equity Securities Gain Loss DebtAndEquitySecuritiesGainLoss	0	USD
CY2019	us-gaap	Available For Sale Securities Gross Realized Gains AvailableForSaleSecuritiesGrossRealizedGains	1000000	USD
CY2018	us-gaap	Available For Sale Securities Gross Realized Gains AvailableForSaleSecuritiesGrossRealizedGains	2000000	USD
CY2019	us-gaap	Available For Sale Securities Gross Realized Losses AvailableForSaleSecuritiesGrossRealizedLosses	8000000	USD
CY2018	us-gaap	Available For Sale Securities Gross Realized Losses AvailableForSaleSecuritiesGrossRealizedLosses	21000000	USD
CY2019	us-gaap	Debt And Equity Securities Gain Loss DebtAndEquitySecuritiesGainLoss	-7000000	USD
CY2018	us-gaap	Debt And Equity Securities Gain Loss DebtAndEquitySecuritiesGainLoss	-19000000	USD
CY2019Q4	us-gaap	Debt Securities Available For Sale Restricted DebtSecuritiesAvailableForSaleRestricted	518000000	USD
CY2019Q4	cma	Liabilities Secured By Pledged Securities LiabilitiesSecuredByPledgedSecurities	418000000	USD
CY2019Q4	us-gaap	Financing Receivable Recorded Investment Past Due FinancingReceivableRecordedInvestmentPastDue	153000000	USD
CY2019Q4	us-gaap	Loans And Leases Receivable Impaired Nonperforming Nonaccrual Of Interest LoansAndLeasesReceivableImpairedNonperformingNonaccrualOfInterest	199000000	USD
CY2019Q4	us-gaap	Financing Receivable Recorded Investment Current FinancingReceivableRecordedInvestmentCurrent	50017000000	USD
CY2019Q4	us-gaap	Loans And Leases Receivable Net Of Deferred Income LoansAndLeasesReceivableNetOfDeferredIncome	50369000000	USD
CY2018Q4	us-gaap	Financing Receivable Recorded Investment Past Due FinancingReceivableRecordedInvestmentPastDue	149000000	USD
CY2018Q4	us-gaap	Loans And Leases Receivable Impaired Nonperforming Nonaccrual Of Interest LoansAndLeasesReceivableImpairedNonperformingNonaccrualOfInterest	221000000	USD
CY2018Q4	us-gaap	Financing Receivable Recorded Investment Current FinancingReceivableRecordedInvestmentCurrent	49793000000	USD
CY2018Q4	us-gaap	Loans And Leases Receivable Net Of Deferred Income LoansAndLeasesReceivableNetOfDeferredIncome	50163000000	USD
CY2019Q4	us-gaap	Loans And Leases Receivable Net Of Deferred Income LoansAndLeasesReceivableNetOfDeferredIncome	50369000000	USD
CY2018Q4	us-gaap	Loans And Leases Receivable Net Of Deferred Income LoansAndLeasesReceivableNetOfDeferredIncome	50163000000	USD
CY2019Q4	us-gaap	Loans And Leases Receivable Impaired Nonperforming Nonaccrual Of Interest LoansAndLeasesReceivableImpairedNonperformingNonaccrualOfInterest	199000000	USD
CY2018Q4	us-gaap	Loans And Leases Receivable Impaired Nonperforming Nonaccrual Of Interest LoansAndLeasesReceivableImpairedNonperformingNonaccrualOfInterest	221000000	USD
CY2019Q4	cma	Reduced Rate Loans ReducedRateLoans	5000000	USD
CY2018Q4	cma	Reduced Rate Loans ReducedRateLoans	8000000	USD
CY2019Q4	cma	Total Nonperforming Loans TotalNonperformingLoans	204000000	USD
CY2018Q4	cma	Total Nonperforming Loans TotalNonperformingLoans	229000000	USD
CY2019Q4	us-gaap	Foreclosed Assets ForeclosedAssets	11000000	USD
CY2018Q4	us-gaap	Foreclosed Assets ForeclosedAssets	1000000	USD
CY2019Q4	cma	Total Nonperforming Assets TotalNonperformingAssets	215000000	USD
CY2018Q4	cma	Total Nonperforming Assets TotalNonperformingAssets	230000000	USD
CY2019Q4	us-gaap	Mortgage Loans In Process Of Foreclosure Amount MortgageLoansInProcessOfForeclosureAmount	0	USD
CY2018Q4	us-gaap	Mortgage Loans In Process Of Foreclosure Amount MortgageLoansInProcessOfForeclosureAmount	1000000	USD
CY2019Q4	us-gaap	Impaired Financing Receivable With No Related Allowance Recorded Investment ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment	86000000	USD
CY2019Q4	us-gaap	Impaired Financing Receivable With Related Allowance Recorded Investment ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment	129000000	USD
CY2019Q4	us-gaap	Impaired Financing Receivable Recorded Investment ImpairedFinancingReceivableRecordedInvestment	215000000	USD
CY2019Q4	us-gaap	Impaired Financing Receivable Unpaid Principal Balance ImpairedFinancingReceivableUnpaidPrincipalBalance	333000000	USD
CY2019Q4	us-gaap	Impaired Financing Receivable Related Allowance ImpairedFinancingReceivableRelatedAllowance	31000000	USD
CY2018Q4	us-gaap	Impaired Financing Receivable With No Related Allowance Recorded Investment ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment	121000000	USD
CY2018Q4	us-gaap	Impaired Financing Receivable With Related Allowance Recorded Investment ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment	155000000	USD
CY2018Q4	us-gaap	Impaired Financing Receivable Recorded Investment ImpairedFinancingReceivableRecordedInvestment	276000000	USD
CY2018Q4	us-gaap	Impaired Financing Receivable Unpaid Principal Balance ImpairedFinancingReceivableUnpaidPrincipalBalance	346000000	USD
CY2018Q4	us-gaap	Impaired Financing Receivable Related Allowance ImpairedFinancingReceivableRelatedAllowance	27000000	USD
CY2019	us-gaap	Impaired Financing Receivable Average Recorded Investment ImpairedFinancingReceivableAverageRecordedInvestment	242000000	USD
CY2019	us-gaap	Impaired Financing Receivable Interest Income Accrual Method ImpairedFinancingReceivableInterestIncomeAccrualMethod	7000000	USD
CY2018	us-gaap	Impaired Financing Receivable Average Recorded Investment ImpairedFinancingReceivableAverageRecordedInvestment	362000000	USD
CY2018	us-gaap	Impaired Financing Receivable Interest Income Accrual Method ImpairedFinancingReceivableInterestIncomeAccrualMethod	9000000	USD
CY2017	us-gaap	Impaired Financing Receivable Average Recorded Investment ImpairedFinancingReceivableAverageRecordedInvestment	551000000	USD
CY2017	us-gaap	Impaired Financing Receivable Interest Income Accrual Method ImpairedFinancingReceivableInterestIncomeAccrualMethod	10000000	USD
CY2019	us-gaap	Financing Receivable Modifications Post Modification Recorded Investment2 FinancingReceivableModificationsPostModificationRecordedInvestment2	29000000	USD
CY2018	us-gaap	Financing Receivable Modifications Post Modification Recorded Investment2 FinancingReceivableModificationsPostModificationRecordedInvestment2	33000000	USD
CY2019Q4	us-gaap	Loans And Leases Receivable Impaired Commitment To Lend LoansAndLeasesReceivableImpairedCommitmentToLend	3000000	USD
CY2018Q4	us-gaap	Loans And Leases Receivable Impaired Commitment To Lend LoansAndLeasesReceivableImpairedCommitmentToLend	20000000	USD
CY2019Q4	cma	Total Automotive Loans TotalAutomotiveLoans	8663000000	USD
CY2018Q4	cma	Total Automotive Loans TotalAutomotiveLoans	9428000000	USD
CY2019Q4	cma	Total Automotive Exposure TotalAutomotiveExposure	12035000000	USD
CY2018Q4	cma	Total Automotive Exposure TotalAutomotiveExposure	12440000000	USD
CY2019Q4	us-gaap	Land Land	86000000	USD
CY2018Q4	us-gaap	Land Land	85000000	USD
CY2019Q4	us-gaap	Buildings And Improvements Gross BuildingsAndImprovementsGross	818000000	USD
CY2018Q4	us-gaap	Buildings And Improvements Gross BuildingsAndImprovementsGross	842000000	USD
CY2019Q4	us-gaap	Furniture And Fixtures Gross FurnitureAndFixturesGross	513000000	USD
CY2018Q4	us-gaap	Furniture And Fixtures Gross FurnitureAndFixturesGross	492000000	USD
CY2019Q4	us-gaap	Property Plant And Equipment Gross PropertyPlantAndEquipmentGross	1417000000	USD
CY2018Q4	us-gaap	Property Plant And Equipment Gross PropertyPlantAndEquipmentGross	1419000000	USD
CY2019Q4	us-gaap	Accumulated Depreciation Depletion And Amortization Property Plant And Equipment AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment	960000000	USD
CY2018Q4	us-gaap	Accumulated Depreciation Depletion And Amortization Property Plant And Equipment AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment	944000000	USD
CY2019Q4	us-gaap	Property Plant And Equipment Net PropertyPlantAndEquipmentNet	457000000	USD
CY2018Q4	us-gaap	Property Plant And Equipment Net PropertyPlantAndEquipmentNet	475000000	USD
CY2019	us-gaap	Lease Cost LeaseCost	81000000	USD
CY2018	us-gaap	Lease Cost LeaseCost	75000000	USD
CY2017	us-gaap	Lease Cost LeaseCost	78000000	USD
CY2019Q4	us-gaap	Goodwill Goodwill	635000000	USD
CY2018Q4	us-gaap	Goodwill Goodwill	635000000	USD
CY2019Q4	cma	Derivative Assets Cash Collateral DerivativeAssetsCashCollateral	12000000	USD
CY2019Q4	us-gaap	Derivative Asset Fair Value Of Collateral DerivativeAssetFairValueOfCollateral	23000000	USD
CY2019Q4	cma	Cash Collateral Posted For Derivatives In Liability Position CashCollateralPostedForDerivativesInLiabilityPosition	15000000	USD
CY2019Q4	us-gaap	Derivative Net Liability Position Aggregate Fair Value DerivativeNetLiabilityPositionAggregateFairValue	0	USD
CY2019Q4	invest	Derivative Notional Amount DerivativeNotionalAmount	30134000000	USD
CY2019Q4	us-gaap	Derivative Fair Value Of Derivative Asset DerivativeFairValueOfDerivativeAsset	317000000	USD
CY2019Q4	us-gaap	Derivative Fair Value Of Derivative Liability DerivativeFairValueOfDerivativeLiability	141000000	USD
CY2018Q4	invest	Derivative Notional Amount DerivativeNotionalAmount	21557000000	USD
CY2018Q4	us-gaap	Derivative Fair Value Of Derivative Asset DerivativeFairValueOfDerivativeAsset	275000000	USD
CY2018Q4	us-gaap	Derivative Fair Value Of Derivative Liability DerivativeFairValueOfDerivativeLiability	269000000	USD
CY2019Q4	us-gaap	Derivative Asset Fair Value Gross Liability DerivativeAssetFairValueGrossLiability	63000000	USD
CY2019Q4	us-gaap	Derivative Liability Fair Value Gross Asset DerivativeLiabilityFairValueGrossAsset	63000000	USD
CY2018Q4	us-gaap	Derivative Asset Fair Value Gross Liability DerivativeAssetFairValueGrossLiability	45000000	USD
CY2018Q4	us-gaap	Derivative Liability Fair Value Gross Asset DerivativeLiabilityFairValueGrossAsset	45000000	USD
CY2019Q4	us-gaap	Derivative Asset Collateral Obligation To Return Cash Offset DerivativeAssetCollateralObligationToReturnCashOffset	11000000	USD
CY2019Q4	us-gaap	Derivative Liability Collateral Right To Reclaim Cash Offset DerivativeLiabilityCollateralRightToReclaimCashOffset	12000000	USD
CY2018Q4	us-gaap	Derivative Asset Collateral Obligation To Return Cash Offset DerivativeAssetCollateralObligationToReturnCashOffset	174000000	USD
CY2018Q4	us-gaap	Derivative Liability Collateral Right To Reclaim Cash Offset DerivativeLiabilityCollateralRightToReclaimCashOffset	1000000	USD
CY2019Q4	us-gaap	Derivative Assets DerivativeAssets	243000000	USD
CY2019Q4	us-gaap	Derivative Liabilities DerivativeLiabilities	66000000	USD
CY2018Q4	us-gaap	Derivative Assets DerivativeAssets	56000000	USD
CY2018Q4	us-gaap	Derivative Liabilities DerivativeLiabilities	223000000	USD
CY2019Q4	us-gaap	Derivative Collateral Obligation To Return Securities DerivativeCollateralObligationToReturnSecurities	0	USD
CY2019Q4	us-gaap	Derivative Collateral Right To Reclaim Securities DerivativeCollateralRightToReclaimSecurities	21000000	USD
CY2018Q4	us-gaap	Derivative Collateral Obligation To Return Securities DerivativeCollateralObligationToReturnSecurities	1000000	USD
CY2018Q4	us-gaap	Derivative Collateral Right To Reclaim Securities DerivativeCollateralRightToReclaimSecurities	0	USD
CY2019Q4	us-gaap	Derivative Fair Value Of Derivative Asset Amount Offset Against Collateral DerivativeFairValueOfDerivativeAssetAmountOffsetAgainstCollateral	243000000	USD
CY2019Q4	us-gaap	Derivative Fair Value Of Derivative Liability Amount Offset Against Collateral DerivativeFairValueOfDerivativeLiabilityAmountOffsetAgainstCollateral	45000000	USD
CY2018Q4	us-gaap	Derivative Fair Value Of Derivative Asset Amount Offset Against Collateral DerivativeFairValueOfDerivativeAssetAmountOffsetAgainstCollateral	55000000	USD
CY2018Q4	us-gaap	Derivative Fair Value Of Derivative Liability Amount Offset Against Collateral DerivativeFairValueOfDerivativeLiabilityAmountOffsetAgainstCollateral	223000000	USD
CY2019Q4	us-gaap	Derivative Credit Risk Valuation Adjustment Derivative Assets DerivativeCreditRiskValuationAdjustmentDerivativeAssets	9000000	USD
CY2018Q4	us-gaap	Derivative Credit Risk Valuation Adjustment Derivative Assets DerivativeCreditRiskValuationAdjustmentDerivativeAssets	2000000	USD
CY2019	us-gaap	Interest Expense Long Term Debt InterestExpenseLongTermDebt	197000000	USD
CY2018	us-gaap	Interest Expense Long Term Debt InterestExpenseLongTermDebt	144000000	USD
CY2019Q4	cma	Cumulative Hedging Adjustmentson Derivative Swap CumulativeHedgingAdjustmentsonDerivativeSwap	146000000	USD
CY2018Q4	cma	Cumulative Hedging Adjustmentson Derivative Swap CumulativeHedgingAdjustmentsonDerivativeSwap	49000000	USD
CY2019Q4	cma	Cumulative Hedging Adjustmentona Discontinued Cash Flow Hedge CumulativeHedgingAdjustmentonaDiscontinuedCashFlowHedge	7000000	USD
CY2018Q4	cma	Cumulative Hedging Adjustmentona Discontinued Cash Flow Hedge CumulativeHedgingAdjustmentonaDiscontinuedCashFlowHedge	8000000	USD
CY2019Q4	cma	Allowance For Off Balance Sheet Credit Losses AllowanceForOffBalanceSheetCreditLosses	31000000	USD
CY2018Q4	cma	Allowance For Off Balance Sheet Credit Losses AllowanceForOffBalanceSheetCreditLosses	30000000	USD
CY2019Q4	cma	Carrying Value Of Unused Commitments To Extend Credit CarryingValueOfUnusedCommitmentsToExtendCredit	25000000	USD
CY2018Q4	cma	Carrying Value Of Unused Commitments To Extend Credit CarryingValueOfUnusedCommitmentsToExtendCredit	24000000	USD
CY2019	cma	Longest Expiration Year Letters Of Credit LongestExpirationYearLettersOfCredit	2028
CY2019Q4	cma	Risk Participations Covering Standby And Commercial Letters Of Credit RiskParticipationsCoveringStandbyAndCommercialLettersOfCredit	161000000	USD
CY2018Q4	cma	Risk Participations Covering Standby And Commercial Letters Of Credit RiskParticipationsCoveringStandbyAndCommercialLettersOfCredit	136000000	USD
CY2019Q4	us-gaap	Letters Of Credit Outstanding Amount LettersOfCreditOutstandingAmount	3300000000	USD
CY2019Q4	cma	Carrying Value Of Standby And Commercial Letters Of Credit CarryingValueOfStandbyAndCommercialLettersOfCredit	32000000	USD
CY2019Q4	cma	Carrying Value Of Standby And Commercial Letters Of Credit Included In Deferred Fees CarryingValueOfStandbyAndCommercialLettersOfCreditIncludedInDeferredFees	26000000	USD
CY2019Q4	cma	Carrying Value Of Standby And Commercial Letters Of Credit Included In Allowance For Credit Losses On Lending Related Commitments CarryingValueOfStandbyAndCommercialLettersOfCreditIncludedInAllowanceForCreditLossesOnLendingRelatedCommitments	6000000	USD
CY2018Q4	cma	Carrying Value Of Standby And Commercial Letters Of Credit CarryingValueOfStandbyAndCommercialLettersOfCredit	34000000	USD
CY2018Q4	cma	Carrying Value Of Standby And Commercial Letters Of Credit Included In Deferred Fees CarryingValueOfStandbyAndCommercialLettersOfCreditIncludedInDeferredFees	28000000	USD
CY2018Q4	cma	Carrying Value Of Standby And Commercial Letters Of Credit Included In Allowance For Credit Losses On Lending Related Commitments CarryingValueOfStandbyAndCommercialLettersOfCreditIncludedInAllowanceForCreditLossesOnLendingRelatedCommitments	6000000	USD
CY2019Q4	cma	Total Internally Classified Watch List Letters Of Credit TotalInternallyClassifiedWatchListLettersOfCredit	44000000	USD
CY2018Q4	cma	Total Internally Classified Watch List Letters Of Credit TotalInternallyClassifiedWatchListLettersOfCredit	49000000	USD
CY2019Q4	cma	Watch List Letters Of Credit As Percentage Of Total Letters Of Credit WatchListLettersOfCreditAsPercentageOfTotalLettersOfCredit	0.013
CY2018Q4	cma	Watch List Letters Of Credit As Percentage Of Total Letters Of Credit WatchListLettersOfCreditAsPercentageOfTotalLettersOfCredit	0.015
CY2019Q4	cma	Notional Amount Of Derivative Credit Risk Participation Agreements NotionalAmountOfDerivativeCreditRiskParticipationAgreements	786000000	USD
CY2018Q4	cma	Notional Amount Of Derivative Credit Risk Participation Agreements NotionalAmountOfDerivativeCreditRiskParticipationAgreements	703000000	USD
CY2019Q4	us-gaap	Credit Derivative Maximum Exposure Undiscounted CreditDerivativeMaximumExposureUndiscounted	20000000	USD
CY2018Q4	us-gaap	Credit Derivative Maximum Exposure Undiscounted CreditDerivativeMaximumExposureUndiscounted	7000000	USD
CY2019Q4	us-gaap	Variable Interest Entity Nonconsolidated Carrying Amount Liabilities VariableInterestEntityNonconsolidatedCarryingAmountLiabilities	160000000	USD
CY2019	us-gaap	Variable Interest Entity Financial Or Other Support Amount VariableInterestEntityFinancialOrOtherSupportAmount	0	USD
CY2019Q4	us-gaap	Time Deposit Maturities Year One TimeDepositMaturitiesYearOne	2970000000	USD
CY2019Q4	us-gaap	Time Deposit Maturities Year Two TimeDepositMaturitiesYearTwo	156000000	USD
CY2019Q4	us-gaap	Time Deposit Maturities Year Three TimeDepositMaturitiesYearThree	24000000	USD
CY2019Q4	us-gaap	Time Deposit Maturities Year Four TimeDepositMaturitiesYearFour	15000000	USD
CY2019Q4	us-gaap	Time Deposit Maturities Year Five TimeDepositMaturitiesYearFive	11000000	USD
CY2019Q4	us-gaap	Time Deposit Maturities After Year Five TimeDepositMaturitiesAfterYearFive	26000000	USD
CY2019Q4	us-gaap	Time Deposits TimeDeposits	3202000000	USD
CY2019Q4	cma	Domestic Time Deposits250000or More DomesticTimeDeposits250000orMore	956000000	USD
CY2018Q4	cma	Domestic Time Deposits250000or More DomesticTimeDeposits250000orMore	543000000	USD
CY2019Q4	us-gaap	Pledged Financial Instruments Not Separately Reported Loans Receivable Pledged For Other Arrangements PledgedFinancialInstrumentsNotSeparatelyReportedLoansReceivablePledgedForOtherArrangements	22000000000.0	USD
CY2019Q4	us-gaap	Line Of Credit Facility Current Borrowing Capacity LineOfCreditFacilityCurrentBorrowingCapacity	17800000000	USD
CY2019Q4	us-gaap	Long Term Debt LongTermDebt	7269000000	USD
CY2018Q4	us-gaap	Long Term Debt LongTermDebt	6463000000	USD
CY2019Q4	us-gaap	Unamortized Debt Issuance Expense UnamortizedDebtIssuanceExpense	12000000	USD
CY2018Q4	us-gaap	Unamortized Debt Issuance Expense UnamortizedDebtIssuanceExpense	8000000	USD
CY2019Q4	us-gaap	Long Term Debt Maturities Repayments Of Principal In Next Twelve Months LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths	675000000	USD
CY2019Q4	us-gaap	Long Term Debt Maturities Repayments Of Principal In Year Two LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo	0	USD
CY2019Q4	us-gaap	Long Term Debt Maturities Repayments Of Principal In Year Three LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree	0	USD
CY2019Q4	us-gaap	Long Term Debt Maturities Repayments Of Principal In Year Four LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour	850000000	USD
CY2019Q4	us-gaap	Long Term Debt Maturities Repayments Of Principal In Year Five LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFive	500000000	USD
CY2019Q4	us-gaap	Long Term Debt Maturities Repayments Of Principal After Year Five LongTermDebtMaturitiesRepaymentsOfPrincipalAfterYearFive	5100000000	USD
CY2019Q4	us-gaap	Debt Instrument Carrying Amount DebtInstrumentCarryingAmount	7125000000	USD
CY2018Q4	us-gaap	Accumulated Other Comprehensive Income Loss Available For Sale Securities Adjustment Net Of Tax AccumulatedOtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax	-138000000	USD
CY2017Q4	us-gaap	Accumulated Other Comprehensive Income Loss Available For Sale Securities Adjustment Net Of Tax AccumulatedOtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax	-101000000	USD
CY2016Q4	us-gaap	Accumulated Other Comprehensive Income Loss Available For Sale Securities Adjustment Net Of Tax AccumulatedOtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax	-33000000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Investment Transferred From Available For Sale To Equity Method Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAociForInvestmentTransferredFromAvailableForSaleToEquityMethodTax	0	USD
CY2018	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Investment Transferred From Available For Sale To Equity Method Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAociForInvestmentTransferredFromAvailableForSaleToEquityMethodTax	1000000	USD
CY2017	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Investment Transferred From Available For Sale To Equity Method Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAociForInvestmentTransferredFromAvailableForSaleToEquityMethodTax	0	USD
CY2019	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Before Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodBeforeTax	257000000	USD
CY2018	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Before Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodBeforeTax	-69000000	USD
CY2017	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Before Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodBeforeTax	-81000000	USD
CY2019	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax	60000000	USD
CY2018	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax	-16000000	USD
CY2017	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax	-27000000	USD
CY2019	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	197000000	USD
CY2018	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	-53000000	USD
CY2017	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	-54000000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesBeforeTax	-8000000	USD
CY2018	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesBeforeTax	-20000000	USD
CY2017	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesBeforeTax	0	USD
CY2019	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesTax	-2000000	USD
CY2018	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesTax	-5000000	USD
CY2017	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesTax	0	USD
CY2019	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Net Of Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesNetOfTax	-6000000	USD
CY2018	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Net Of Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesNetOfTax	-15000000	USD
CY2017	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Net Of Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesNetOfTax	0	USD
CY2019	cma	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Amortization Of Unrealized Losses On Afs Securities Transferred To Htm Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForAmortizationOfUnrealizedLossesOnAFSSecuritiesTransferredToHTMBeforeTax	0	USD
CY2018	cma	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Amortization Of Unrealized Losses On Afs Securities Transferred To Htm Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForAmortizationOfUnrealizedLossesOnAFSSecuritiesTransferredToHTMBeforeTax	0	USD
CY2017	cma	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Amortization Of Unrealized Losses On Afs Securities Transferred To Htm Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForAmortizationOfUnrealizedLossesOnAFSSecuritiesTransferredToHTMBeforeTax	-3000000	USD
CY2019	cma	Other Comprehensive Income Loss Reclassification From Aoci For Amortization Of Yield Adjustment Tax OtherComprehensiveIncomeLossReclassificationFromAOCIForAmortizationOfYieldAdjustmentTax	0	USD
CY2018	cma	Other Comprehensive Income Loss Reclassification From Aoci For Amortization Of Yield Adjustment Tax OtherComprehensiveIncomeLossReclassificationFromAOCIForAmortizationOfYieldAdjustmentTax	0	USD
CY2017	cma	Other Comprehensive Income Loss Reclassification From Aoci For Amortization Of Yield Adjustment Tax OtherComprehensiveIncomeLossReclassificationFromAOCIForAmortizationOfYieldAdjustmentTax	-1000000	USD
CY2019	cma	Other Comprehensiveincome Loss Reclassification Adjustment From Aoci For Amortization Of Unrealized Gains Losses On Securities Transferred From Available For Sale To Held To Maturity Net Of Tax OtherComprehensiveincomeLossReclassificationAdjustmentFromAOCIForAmortizationOfUnrealizedGainsLossesOnSecuritiesTransferredFromAvailableForSaleToHeldToMaturityNetOfTax	0	USD
CY2018	cma	Other Comprehensiveincome Loss Reclassification Adjustment From Aoci For Amortization Of Unrealized Gains Losses On Securities Transferred From Available For Sale To Held To Maturity Net Of Tax OtherComprehensiveincomeLossReclassificationAdjustmentFromAOCIForAmortizationOfUnrealizedGainsLossesOnSecuritiesTransferredFromAvailableForSaleToHeldToMaturityNetOfTax	0	USD
CY2017	cma	Other Comprehensiveincome Loss Reclassification Adjustment From Aoci For Amortization Of Unrealized Gains Losses On Securities Transferred From Available For Sale To Held To Maturity Net Of Tax OtherComprehensiveincomeLossReclassificationAdjustmentFromAOCIForAmortizationOfUnrealizedGainsLossesOnSecuritiesTransferredFromAvailableForSaleToHeldToMaturityNetOfTax	-2000000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Adjustment Net Of Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax	203000000	USD
CY2018	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Adjustment Net Of Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax	-38000000	USD
CY2017	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Adjustment Net Of Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax	-52000000	USD
CY2019	cma	Reclassificationof Certain Tax Effectsfrom Accumulated Other Comprehensive Income ReclassificationofCertainTaxEffectsfromAccumulatedOtherComprehensiveIncome	0	USD
CY2018	cma	Reclassificationof Certain Tax Effectsfrom Accumulated Other Comprehensive Income ReclassificationofCertainTaxEffectsfromAccumulatedOtherComprehensiveIncome	0	USD
CY2017	cma	Reclassificationof Certain Tax Effectsfrom Accumulated Other Comprehensive Income ReclassificationofCertainTaxEffectsfromAccumulatedOtherComprehensiveIncome	-16000000	USD
CY2019Q4	us-gaap	Accumulated Other Comprehensive Income Loss Available For Sale Securities Adjustment Net Of Tax AccumulatedOtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax	65000000	USD
CY2018Q4	us-gaap	Accumulated Other Comprehensive Income Loss Available For Sale Securities Adjustment Net Of Tax AccumulatedOtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax	-138000000	USD
CY2017Q4	us-gaap	Accumulated Other Comprehensive Income Loss Available For Sale Securities Adjustment Net Of Tax AccumulatedOtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax	-101000000	USD
CY2018Q4	us-gaap	Accumulated Other Comprehensive Income Loss Cumulative Changes In Net Gain Loss From Cash Flow Hedges Effect Net Of Tax AccumulatedOtherComprehensiveIncomeLossCumulativeChangesInNetGainLossFromCashFlowHedgesEffectNetOfTax	0	USD
CY2017Q4	us-gaap	Accumulated Other Comprehensive Income Loss Cumulative Changes In Net Gain Loss From Cash Flow Hedges Effect Net Of Tax AccumulatedOtherComprehensiveIncomeLossCumulativeChangesInNetGainLossFromCashFlowHedgesEffectNetOfTax	0	USD
CY2016Q4	us-gaap	Accumulated Other Comprehensive Income Loss Cumulative Changes In Net Gain Loss From Cash Flow Hedges Effect Net Of Tax AccumulatedOtherComprehensiveIncomeLossCumulativeChangesInNetGainLossFromCashFlowHedgesEffectNetOfTax	0	USD
CY2019	us-gaap	Other Comprehensive Income Unrealized Gain Loss On Derivatives Arising During Period Before Tax OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodBeforeTax	44000000	USD
CY2018	us-gaap	Other Comprehensive Income Unrealized Gain Loss On Derivatives Arising During Period Before Tax OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodBeforeTax	0	USD
CY2017	us-gaap	Other Comprehensive Income Unrealized Gain Loss On Derivatives Arising During Period Before Tax OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodBeforeTax	0	USD
CY2019	us-gaap	Other Comprehensive Income Unrealized Gain Loss On Derivatives Arising During Period Tax OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodTax	10000000	USD
CY2018	us-gaap	Other Comprehensive Income Unrealized Gain Loss On Derivatives Arising During Period Tax OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodTax	0	USD
CY2017	us-gaap	Other Comprehensive Income Unrealized Gain Loss On Derivatives Arising During Period Tax OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodTax	0	USD
CY2019	us-gaap	Other Comprehensive Income Loss Derivatives Qualifying As Hedges Net Of Tax OtherComprehensiveIncomeLossDerivativesQualifyingAsHedgesNetOfTax	34000000	USD
CY2018	us-gaap	Other Comprehensive Income Loss Derivatives Qualifying As Hedges Net Of Tax OtherComprehensiveIncomeLossDerivativesQualifyingAsHedgesNetOfTax	0	USD
CY2017	us-gaap	Other Comprehensive Income Loss Derivatives Qualifying As Hedges Net Of Tax OtherComprehensiveIncomeLossDerivativesQualifyingAsHedgesNetOfTax	0	USD
CY2019Q4	us-gaap	Accumulated Other Comprehensive Income Loss Cumulative Changes In Net Gain Loss From Cash Flow Hedges Effect Net Of Tax AccumulatedOtherComprehensiveIncomeLossCumulativeChangesInNetGainLossFromCashFlowHedgesEffectNetOfTax	34000000	USD
CY2018Q4	us-gaap	Accumulated Other Comprehensive Income Loss Cumulative Changes In Net Gain Loss From Cash Flow Hedges Effect Net Of Tax AccumulatedOtherComprehensiveIncomeLossCumulativeChangesInNetGainLossFromCashFlowHedgesEffectNetOfTax	0	USD
CY2017Q4	us-gaap	Accumulated Other Comprehensive Income Loss Cumulative Changes In Net Gain Loss From Cash Flow Hedges Effect Net Of Tax AccumulatedOtherComprehensiveIncomeLossCumulativeChangesInNetGainLossFromCashFlowHedgesEffectNetOfTax	0	USD
CY2018Q4	us-gaap	Accumulated Other Comprehensive Income Loss Defined Benefit Pension And Other Postretirement Plans Net Of Tax AccumulatedOtherComprehensiveIncomeLossDefinedBenefitPensionAndOtherPostretirementPlansNetOfTax	-471000000	USD
CY2017Q4	us-gaap	Accumulated Other Comprehensive Income Loss Defined Benefit Pension And Other Postretirement Plans Net Of Tax AccumulatedOtherComprehensiveIncomeLossDefinedBenefitPensionAndOtherPostretirementPlansNetOfTax	-350000000	USD
CY2016Q4	us-gaap	Accumulated Other Comprehensive Income Loss Defined Benefit Pension And Other Postretirement Plans Net Of Tax AccumulatedOtherComprehensiveIncomeLossDefinedBenefitPensionAndOtherPostretirementPlansNetOfTax	-350000000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Net Unamortized Gain Loss Arising During Period Before Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansNetUnamortizedGainLossArisingDuringPeriodBeforeTax	163000000	USD
CY2018	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Net Unamortized Gain Loss Arising During Period Before Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansNetUnamortizedGainLossArisingDuringPeriodBeforeTax	-191000000	USD
CY2017	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Net Unamortized Gain Loss Arising During Period Before Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansNetUnamortizedGainLossArisingDuringPeriodBeforeTax	72000000	USD
CY2019	us-gaap	Other Comprehensive Income Defined Benefit Plans Net Unamortized Gain Loss Arising During Period Tax OtherComprehensiveIncomeDefinedBenefitPlansNetUnamortizedGainLossArisingDuringPeriodTax	38000000	USD
CY2018	us-gaap	Other Comprehensive Income Defined Benefit Plans Net Unamortized Gain Loss Arising During Period Tax OtherComprehensiveIncomeDefinedBenefitPlansNetUnamortizedGainLossArisingDuringPeriodTax	-44000000	USD
CY2017	us-gaap	Other Comprehensive Income Defined Benefit Plans Net Unamortized Gain Loss Arising During Period Tax OtherComprehensiveIncomeDefinedBenefitPlansNetUnamortizedGainLossArisingDuringPeriodTax	17000000	USD
CY2019	us-gaap	Other Comprehensive Income Defined Benefit Plans Net Unamortized Gain Loss Arising During Period Net Of Tax OtherComprehensiveIncomeDefinedBenefitPlansNetUnamortizedGainLossArisingDuringPeriodNetOfTax	125000000	USD
CY2018	us-gaap	Other Comprehensive Income Defined Benefit Plans Net Unamortized Gain Loss Arising During Period Net Of Tax OtherComprehensiveIncomeDefinedBenefitPlansNetUnamortizedGainLossArisingDuringPeriodNetOfTax	-147000000	USD
CY2017	us-gaap	Other Comprehensive Income Defined Benefit Plans Net Unamortized Gain Loss Arising During Period Net Of Tax OtherComprehensiveIncomeDefinedBenefitPlansNetUnamortizedGainLossArisingDuringPeriodNetOfTax	55000000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci Pension And Other Postretirement Benefit Plans For Net Gain Loss Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetGainLossBeforeTax	42000000	USD
CY2018	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci Pension And Other Postretirement Benefit Plans For Net Gain Loss Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetGainLossBeforeTax	61000000	USD
CY2017	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci Pension And Other Postretirement Benefit Plans For Net Gain Loss Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetGainLossBeforeTax	51000000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Amortization Adjustment From Aoci Pension And Other Postretirement Benefit Plans For Net Prior Service Cost Credit Before Tax OtherComprehensiveIncomeLossAmortizationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetPriorServiceCostCreditBeforeTax	-27000000	USD
CY2018	us-gaap	Other Comprehensive Income Loss Amortization Adjustment From Aoci Pension And Other Postretirement Benefit Plans For Net Prior Service Cost Credit Before Tax OtherComprehensiveIncomeLossAmortizationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetPriorServiceCostCreditBeforeTax	-27000000	USD
CY2017	us-gaap	Other Comprehensive Income Loss Amortization Adjustment From Aoci Pension And Other Postretirement Benefit Plans For Net Prior Service Cost Credit Before Tax OtherComprehensiveIncomeLossAmortizationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetPriorServiceCostCreditBeforeTax	-27000000	USD
CY2019	cma	Other Comprehensive Income Loss Reclassification Adjustment Pension And Other Postretirement Benefit Plans Recognized In Net Periodic Defined Benefit Cost Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentPensionAndOtherPostretirementBenefitPlansRecognizedInNetPeriodicDefinedBenefitCostBeforeTax	15000000	USD
CY2018	cma	Other Comprehensive Income Loss Reclassification Adjustment Pension And Other Postretirement Benefit Plans Recognized In Net Periodic Defined Benefit Cost Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentPensionAndOtherPostretirementBenefitPlansRecognizedInNetPeriodicDefinedBenefitCostBeforeTax	34000000	USD
CY2017	cma	Other Comprehensive Income Loss Reclassification Adjustment Pension And Other Postretirement Benefit Plans Recognized In Net Periodic Defined Benefit Cost Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentPensionAndOtherPostretirementBenefitPlansRecognizedInNetPeriodicDefinedBenefitCostBeforeTax	24000000	USD
CY2019	cma	Other Comprehensive Income Loss Reclassification Adjustment Pension And Other Postretirement Benefit Plans Recognized In Net Periodic Defined Benefit Cost Tax OtherComprehensiveIncomeLossReclassificationAdjustmentPensionAndOtherPostretirementBenefitPlansRecognizedInNetPeriodicDefinedBenefitCostTax	3000000	USD
CY2018	cma	Other Comprehensive Income Loss Reclassification Adjustment Pension And Other Postretirement Benefit Plans Recognized In Net Periodic Defined Benefit Cost Tax OtherComprehensiveIncomeLossReclassificationAdjustmentPensionAndOtherPostretirementBenefitPlansRecognizedInNetPeriodicDefinedBenefitCostTax	8000000	USD
CY2017	cma	Other Comprehensive Income Loss Reclassification Adjustment Pension And Other Postretirement Benefit Plans Recognized In Net Periodic Defined Benefit Cost Tax OtherComprehensiveIncomeLossReclassificationAdjustmentPensionAndOtherPostretirementBenefitPlansRecognizedInNetPeriodicDefinedBenefitCostTax	8000000	USD
CY2019	cma	Other Comprehensive Income Loss Reclassification Adjustment Pension And Other Postretirement Benefit Plans Recognized In Net Periodic Defined Benefit Cost Net Of Tax OtherComprehensiveIncomeLossReclassificationAdjustmentPensionAndOtherPostretirementBenefitPlansRecognizedInNetPeriodicDefinedBenefitCostNetOfTax	12000000	USD
CY2018	cma	Other Comprehensive Income Loss Reclassification Adjustment Pension And Other Postretirement Benefit Plans Recognized In Net Periodic Defined Benefit Cost Net Of Tax OtherComprehensiveIncomeLossReclassificationAdjustmentPensionAndOtherPostretirementBenefitPlansRecognizedInNetPeriodicDefinedBenefitCostNetOfTax	26000000	USD
CY2017	cma	Other Comprehensive Income Loss Reclassification Adjustment Pension And Other Postretirement Benefit Plans Recognized In Net Periodic Defined Benefit Cost Net Of Tax OtherComprehensiveIncomeLossReclassificationAdjustmentPensionAndOtherPostretirementBenefitPlansRecognizedInNetPeriodicDefinedBenefitCostNetOfTax	16000000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Adjustment Net Of Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax	-137000000	USD
CY2018	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Adjustment Net Of Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax	121000000	USD
CY2017	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Adjustment Net Of Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax	-71000000	USD
CY2019	cma	Reclassificationof Certain Tax Effectsfrom Accumulated Other Comprehensive Incomefor Benefit Plans ReclassificationofCertainTaxEffectsfromAccumulatedOtherComprehensiveIncomeforBenefitPlans	0	USD
CY2018	cma	Reclassificationof Certain Tax Effectsfrom Accumulated Other Comprehensive Incomefor Benefit Plans ReclassificationofCertainTaxEffectsfromAccumulatedOtherComprehensiveIncomeforBenefitPlans	0	USD
CY2017	cma	Reclassificationof Certain Tax Effectsfrom Accumulated Other Comprehensive Incomefor Benefit Plans ReclassificationofCertainTaxEffectsfromAccumulatedOtherComprehensiveIncomeforBenefitPlans	-71000000	USD
CY2019Q4	us-gaap	Accumulated Other Comprehensive Income Loss Defined Benefit Pension And Other Postretirement Plans Net Of Tax AccumulatedOtherComprehensiveIncomeLossDefinedBenefitPensionAndOtherPostretirementPlansNetOfTax	-334000000	USD
CY2018Q4	us-gaap	Accumulated Other Comprehensive Income Loss Defined Benefit Pension And Other Postretirement Plans Net Of Tax AccumulatedOtherComprehensiveIncomeLossDefinedBenefitPensionAndOtherPostretirementPlansNetOfTax	-471000000	USD
CY2017Q4	us-gaap	Accumulated Other Comprehensive Income Loss Defined Benefit Pension And Other Postretirement Plans Net Of Tax AccumulatedOtherComprehensiveIncomeLossDefinedBenefitPensionAndOtherPostretirementPlansNetOfTax	-350000000	USD
CY2019Q4	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	-235000000	USD
CY2018Q4	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	-609000000	USD
CY2017Q4	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	-451000000	USD
CY2019	us-gaap	Profit Loss ProfitLoss	1198000000	USD
CY2018	us-gaap	Profit Loss ProfitLoss	1235000000	USD
CY2017	us-gaap	Profit Loss ProfitLoss	743000000	USD
CY2019	us-gaap	Undistributed Earnings Loss Allocated To Participating Securities Diluted UndistributedEarningsLossAllocatedToParticipatingSecuritiesDiluted	7000000	USD
CY2018	us-gaap	Undistributed Earnings Loss Allocated To Participating Securities Diluted UndistributedEarningsLossAllocatedToParticipatingSecuritiesDiluted	8000000	USD
CY2017	us-gaap	Undistributed Earnings Loss Allocated To Participating Securities Diluted UndistributedEarningsLossAllocatedToParticipatingSecuritiesDiluted	5000000	USD
CY2019	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	1191000000	USD
CY2018	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	1227000000	USD
CY2017	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	738000000	USD
CY2019	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	150000000	shares
CY2018	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	168000000	shares
CY2017	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	174000000	shares
CY2019	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	7.95
CY2018	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	7.31
CY2017	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	4.23
CY2019	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	150000000	shares
CY2018	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	168000000	shares
CY2017	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	174000000	shares
CY2019	us-gaap	Incremental Common Shares Attributable To Share Based Payment Arrangements IncrementalCommonSharesAttributableToShareBasedPaymentArrangements	1000000	shares
CY2018	us-gaap	Incremental Common Shares Attributable To Share Based Payment Arrangements IncrementalCommonSharesAttributableToShareBasedPaymentArrangements	2000000	shares
CY2017	us-gaap	Incremental Common Shares Attributable To Share Based Payment Arrangements IncrementalCommonSharesAttributableToShareBasedPaymentArrangements	3000000	shares
CY2019	us-gaap	Incremental Common Shares Attributable To Call Options And Warrants IncrementalCommonSharesAttributableToCallOptionsAndWarrants	0	shares
CY2018	us-gaap	Incremental Common Shares Attributable To Call Options And Warrants IncrementalCommonSharesAttributableToCallOptionsAndWarrants	1000000	shares
CY2017	us-gaap	Incremental Common Shares Attributable To Call Options And Warrants IncrementalCommonSharesAttributableToCallOptionsAndWarrants	1000000	shares
CY2019	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	151000000	shares
CY2018	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	171000000	shares
CY2017	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	178000000	shares
CY2019	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	7.87
CY2018	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	7.20
CY2017	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	4.14
CY2019	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	39000000	USD
CY2018	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	48000000	USD
CY2017	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	39000000	USD
CY2019	us-gaap	Employee Service Share Based Compensation Tax Benefit From Compensation Expense EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense	9000000	USD
CY2018	us-gaap	Employee Service Share Based Compensation Tax Benefit From Compensation Expense EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense	11000000	USD
CY2017	us-gaap	Employee Service Share Based Compensation Tax Benefit From Compensation Expense EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense	14000000	USD
CY2019Q4	us-gaap	Employee Service Share Based Compensation Nonvested Awards Total Compensation Cost Not Yet Recognized EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized	33000000	USD
CY2019Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Number Of Shares Authorized ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized	6100000	shares
CY2019Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Number Of Shares Available For Grant ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant	5000000	shares
CY2019	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Grants In Period Weighted Average Grant Date Fair Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue	22.27
CY2018	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Grants In Period Weighted Average Grant Date Fair Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue	30.32
CY2017	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Grants In Period Weighted Average Grant Date Fair Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue	19.61
CY2019	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Risk Free Interest Rate ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate	0.0274
CY2018	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Risk Free Interest Rate ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate	0.0263
CY2017	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Risk Free Interest Rate ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate	0.0247
CY2019	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Expected Dividend Rate ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate	0.0300
CY2018	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Expected Dividend Rate ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate	0.0300
CY2017	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Expected Dividend Rate ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate	0.0300
CY2019	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Expected Volatility Rate ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate	0.30
CY2018	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Expected Volatility Rate ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate	0.36
CY2017	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Expected Volatility Rate ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate	0.34
CY2019Q4	us-gaap	Share Price SharePrice	71.75
CY2019	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Exercises In Period Total Intrinsic Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue	20000000	USD
CY2018	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Exercises In Period Total Intrinsic Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue	81000000	USD
CY2017	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Exercises In Period Total Intrinsic Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue	104000000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Net Unamortized Gain Loss Arising During Period Before Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansNetUnamortizedGainLossArisingDuringPeriodBeforeTax	163000000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci Pension And Other Postretirement Benefit Plans For Net Gain Loss Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetGainLossBeforeTax	42000000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Amortization Adjustment From Aoci Pension And Other Postretirement Benefit Plans For Net Prior Service Cost Credit Before Tax OtherComprehensiveIncomeLossAmortizationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetPriorServiceCostCreditBeforeTax	-27000000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Adjustment Before Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentBeforeTax	-178000000	USD
CY2019Q4	us-gaap	Defined Benefit Plan Expected Amortization Of Gain Loss Next Fiscal Year DefinedBenefitPlanExpectedAmortizationOfGainLossNextFiscalYear	64000000	USD
CY2019Q4	us-gaap	Defined Benefit Plan Expected Amortization Of Prior Service Cost Credit Next Fiscal Year DefinedBenefitPlanExpectedAmortizationOfPriorServiceCostCreditNextFiscalYear	27000000	USD
CY2019	us-gaap	Defined Benefit Plan Effect Of One Percentage Point Increase On Accumulated Postretirement Benefit Obligation DefinedBenefitPlanEffectOfOnePercentagePointIncreaseOnAccumulatedPostretirementBenefitObligation	0.05	USD
CY2019Q4	cma	Assets Fair Value Disclosure Excluding Assets Valuedat Nav AssetsFairValueDisclosureExcludingAssetsValuedatNAV	2480000000	USD
CY2019Q4	us-gaap	Defined Benefit Plan Fair Value Of Plan Assets DefinedBenefitPlanFairValueOfPlanAssets	2949000000	USD
CY2018Q4	cma	Assets Fair Value Disclosure Excluding Assets Valuedat Nav AssetsFairValueDisclosureExcludingAssetsValuedatNAV	2070000000	USD
CY2018Q4	us-gaap	Defined Benefit Plan Fair Value Of Plan Assets DefinedBenefitPlanFairValueOfPlanAssets	2462000000	USD
CY2019Q4	us-gaap	Defined Benefit Plan Expected Future Employer Contributions Next Fiscal Year DefinedBenefitPlanExpectedFutureEmployerContributionsNextFiscalYear	0	USD
CY2019	cma	Defined Contribution Plan Total Qualified Earnings Matching Cash Contributions By Employer Percent DefinedContributionPlanTotalQualifiedEarningsMatchingCashContributionsByEmployerPercent	1
CY2019	us-gaap	Defined Contribution Plan Employer Matching Contribution Percent DefinedContributionPlanEmployerMatchingContributionPercent	0.04
CY2019	us-gaap	Defined Contribution Plan Cost Recognized DefinedContributionPlanCostRecognized	22000000	USD
CY2019	us-gaap	Current Federal Tax Expense Benefit CurrentFederalTaxExpenseBenefit	267000000	USD
CY2018	us-gaap	Current Federal Tax Expense Benefit CurrentFederalTaxExpenseBenefit	227000000	USD
CY2017	us-gaap	Current Federal Tax Expense Benefit CurrentFederalTaxExpenseBenefit	371000000	USD
CY2019	us-gaap	Current Foreign Tax Expense Benefit CurrentForeignTaxExpenseBenefit	7000000	USD
CY2018	us-gaap	Current Foreign Tax Expense Benefit CurrentForeignTaxExpenseBenefit	10000000	USD
CY2017	us-gaap	Current Foreign Tax Expense Benefit CurrentForeignTaxExpenseBenefit	5000000	USD
CY2019	us-gaap	Current State And Local Tax Expense Benefit CurrentStateAndLocalTaxExpenseBenefit	48000000	USD
CY2018	us-gaap	Current State And Local Tax Expense Benefit CurrentStateAndLocalTaxExpenseBenefit	39000000	USD
CY2017	us-gaap	Current State And Local Tax Expense Benefit CurrentStateAndLocalTaxExpenseBenefit	36000000	USD
CY2019	us-gaap	Current Income Tax Expense Benefit CurrentIncomeTaxExpenseBenefit	322000000	USD
CY2018	us-gaap	Current Income Tax Expense Benefit CurrentIncomeTaxExpenseBenefit	276000000	USD
CY2017	us-gaap	Current Income Tax Expense Benefit CurrentIncomeTaxExpenseBenefit	412000000	USD
CY2019	us-gaap	Deferred Federal Income Tax Expense Benefit DeferredFederalIncomeTaxExpenseBenefit	16000000	USD
CY2018	us-gaap	Deferred Federal Income Tax Expense Benefit DeferredFederalIncomeTaxExpenseBenefit	29000000	USD
CY2017	us-gaap	Deferred Federal Income Tax Expense Benefit DeferredFederalIncomeTaxExpenseBenefit	-26000000	USD
CY2019	us-gaap	Deferred State And Local Income Tax Expense Benefit DeferredStateAndLocalIncomeTaxExpenseBenefit	-4000000	USD
CY2018	us-gaap	Deferred State And Local Income Tax Expense Benefit DeferredStateAndLocalIncomeTaxExpenseBenefit	3000000	USD
CY2017	us-gaap	Deferred State And Local Income Tax Expense Benefit DeferredStateAndLocalIncomeTaxExpenseBenefit	-2000000	USD
CY2019	cma	Remeasurementofdeferredtaxes Remeasurementofdeferredtaxes	0	USD
CY2018	cma	Remeasurementofdeferredtaxes Remeasurementofdeferredtaxes	-8000000	USD
CY2017	cma	Remeasurementofdeferredtaxes Remeasurementofdeferredtaxes	107000000	USD
CY2019	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	12000000	USD
CY2018	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	24000000	USD
CY2017	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	79000000	USD
CY2019	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	334000000	USD
CY2018	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	300000000	USD
CY2017	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	491000000	USD
CY2019	cma	Income Loss From Continuing Operations Before Income Taxes IncomeLossFromContinuingOperationsBeforeIncomeTaxes	1500000000	USD
CY2019	us-gaap	Income Loss From Continuing Operations Before Income Taxes Foreign IncomeLossFromContinuingOperationsBeforeIncomeTaxesForeign	42000000	USD
CY2018	cma	Reductionindeferredtaxadjustment Reductionindeferredtaxadjustment	99000000	USD
CY2018	cma	Deferredtaxadjustmentfor Tax Cutand Jobact DeferredtaxadjustmentforTaxCutandJobact	-8000000	USD
CY2019	us-gaap	Income Tax Reconciliation Income Tax Expense Benefit At Federal Statutory Income Tax Rate IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate	322000000	USD
CY2019	us-gaap	Effective Income Tax Rate Reconciliation At Federal Statutory Income Tax Rate EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate	0.210
CY2018	us-gaap	Income Tax Reconciliation Income Tax Expense Benefit At Federal Statutory Income Tax Rate IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate	323000000	USD
CY2018	us-gaap	Effective Income Tax Rate Reconciliation At Federal Statutory Income Tax Rate EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate	0.210
CY2017	us-gaap	Income Tax Reconciliation Income Tax Expense Benefit At Federal Statutory Income Tax Rate IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate	432000000	USD
CY2017	us-gaap	Effective Income Tax Rate Reconciliation At Federal Statutory Income Tax Rate EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate	0.350
CY2019	us-gaap	Income Tax Reconciliation State And Local Income Taxes IncomeTaxReconciliationStateAndLocalIncomeTaxes	33000000	USD
CY2019	us-gaap	Effective Income Tax Rate Reconciliation State And Local Income Taxes EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes	0.022
CY2018	us-gaap	Income Tax Reconciliation State And Local Income Taxes IncomeTaxReconciliationStateAndLocalIncomeTaxes	35000000	USD
CY2018	us-gaap	Effective Income Tax Rate Reconciliation State And Local Income Taxes EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes	0.023
CY2017	us-gaap	Income Tax Reconciliation State And Local Income Taxes IncomeTaxReconciliationStateAndLocalIncomeTaxes	22000000	USD
CY2017	us-gaap	Effective Income Tax Rate Reconciliation State And Local Income Taxes EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes	0.018
CY2019	cma	Taxbenefitsfromemployeestocktransactions Taxbenefitsfromemployeestocktransactions	12000000	USD
CY2019	cma	Income Tax Effects Allocated Directlyto Equity Employee Stock Options Percentage IncomeTaxEffectsAllocatedDirectlytoEquityEmployeeStockOptionsPercentage	-0.008
CY2018	cma	Taxbenefitsfromemployeestocktransactions Taxbenefitsfromemployeestocktransactions	23000000	USD
CY2018	cma	Income Tax Effects Allocated Directlyto Equity Employee Stock Options Percentage IncomeTaxEffectsAllocatedDirectlytoEquityEmployeeStockOptionsPercentage	-0.015
CY2017	cma	Taxbenefitsfromemployeestocktransactions Taxbenefitsfromemployeestocktransactions	35000000	USD
CY2017	cma	Income Tax Effects Allocated Directlyto Equity Employee Stock Options Percentage IncomeTaxEffectsAllocatedDirectlytoEquityEmployeeStockOptionsPercentage	-0.028
CY2019	cma	Tax Capitalizationandrecovery TaxCapitalizationandrecovery	0	USD
CY2019	cma	Tax Capitalizationandrecoverypercent TaxCapitalizationandrecoverypercent	0
CY2018	cma	Tax Capitalizationandrecovery TaxCapitalizationandrecovery	-17000000	USD
CY2018	cma	Tax Capitalizationandrecoverypercent TaxCapitalizationandrecoverypercent	-0.011
CY2017	cma	Tax Capitalizationandrecovery TaxCapitalizationandrecovery	0	USD
CY2017	cma	Tax Capitalizationandrecoverypercent TaxCapitalizationandrecoverypercent	0
CY2019	us-gaap	Income Tax Reconciliation Tax Credits Other IncomeTaxReconciliationTaxCreditsOther	11000000	USD
CY2019	us-gaap	Effective Income Tax Rate Reconciliation Tax Credits Other EffectiveIncomeTaxRateReconciliationTaxCreditsOther	0.007
CY2018	us-gaap	Income Tax Reconciliation Tax Credits Other IncomeTaxReconciliationTaxCreditsOther	12000000	USD
CY2018	us-gaap	Effective Income Tax Rate Reconciliation Tax Credits Other EffectiveIncomeTaxRateReconciliationTaxCreditsOther	0.008
CY2017	us-gaap	Income Tax Reconciliation Tax Credits Other IncomeTaxReconciliationTaxCreditsOther	21000000	USD
CY2017	us-gaap	Effective Income Tax Rate Reconciliation Tax Credits Other EffectiveIncomeTaxRateReconciliationTaxCreditsOther	0.017
CY2019	us-gaap	Income Tax Reconciliation Tax Exempt Income IncomeTaxReconciliationTaxExemptIncome	9000000	USD
CY2019	us-gaap	Effective Income Tax Rate Reconciliation Tax Exempt Income EffectiveIncomeTaxRateReconciliationTaxExemptIncome	0.006
CY2018	us-gaap	Income Tax Reconciliation Tax Exempt Income IncomeTaxReconciliationTaxExemptIncome	9000000	USD
CY2018	us-gaap	Effective Income Tax Rate Reconciliation Tax Exempt Income EffectiveIncomeTaxRateReconciliationTaxExemptIncome	0.006
CY2017	us-gaap	Income Tax Reconciliation Tax Exempt Income IncomeTaxReconciliationTaxExemptIncome	16000000	USD
CY2017	us-gaap	Effective Income Tax Rate Reconciliation Tax Exempt Income EffectiveIncomeTaxRateReconciliationTaxExemptIncome	0.013
CY2019	cma	Deferredtaxadjustmentfor Tax Cutand Jobact DeferredtaxadjustmentforTaxCutandJobact	0	USD
CY2019	cma	Deferred Tax Adjustmentfor Tax Cutad Job Act Percentage DeferredTaxAdjustmentforTaxCutadJobActPercentage	0
CY2018	cma	Deferredtaxadjustmentfor Tax Cutand Jobact DeferredtaxadjustmentforTaxCutandJobact	-8000000	USD
CY2018	cma	Deferred Tax Adjustmentfor Tax Cutad Job Act Percentage DeferredTaxAdjustmentforTaxCutadJobActPercentage	-0.005
CY2017	cma	Deferredtaxadjustmentfor Tax Cutand Jobact DeferredtaxadjustmentforTaxCutandJobact	107000000	USD
CY2017	cma	Deferred Tax Adjustmentfor Tax Cutad Job Act Percentage DeferredTaxAdjustmentforTaxCutadJobActPercentage	0.087
CY2019	us-gaap	Income Tax Reconciliation Nondeductible Expense Other IncomeTaxReconciliationNondeductibleExpenseOther	5000000	USD
CY2019	us-gaap	Effective Income Tax Rate Reconciliation Nondeductible Expense Other EffectiveIncomeTaxRateReconciliationNondeductibleExpenseOther	0.003
CY2018	us-gaap	Income Tax Reconciliation Nondeductible Expense Other IncomeTaxReconciliationNondeductibleExpenseOther	8000000	USD
CY2018	us-gaap	Effective Income Tax Rate Reconciliation Nondeductible Expense Other EffectiveIncomeTaxRateReconciliationNondeductibleExpenseOther	0.005
CY2017	us-gaap	Income Tax Reconciliation Nondeductible Expense Other IncomeTaxReconciliationNondeductibleExpenseOther	0	USD
CY2017	us-gaap	Effective Income Tax Rate Reconciliation Nondeductible Expense Other EffectiveIncomeTaxRateReconciliationNondeductibleExpenseOther	0
CY2019	us-gaap	Income Tax Reconciliation Tax Contingencies Other IncomeTaxReconciliationTaxContingenciesOther	0	USD
CY2019	us-gaap	Effective Income Tax Rate Reconciliation Tax Contingencies Other EffectiveIncomeTaxRateReconciliationTaxContingenciesOther	0
CY2018	us-gaap	Income Tax Reconciliation Tax Contingencies Other IncomeTaxReconciliationTaxContingenciesOther	4000000	USD
CY2018	us-gaap	Effective Income Tax Rate Reconciliation Tax Contingencies Other EffectiveIncomeTaxRateReconciliationTaxContingenciesOther	0.003
CY2017	us-gaap	Income Tax Reconciliation Tax Contingencies Other IncomeTaxReconciliationTaxContingenciesOther	0	USD
CY2017	us-gaap	Effective Income Tax Rate Reconciliation Tax Contingencies Other EffectiveIncomeTaxRateReconciliationTaxContingenciesOther	0
CY2019	cma	Income Tax Reconciliation Interest On Income Tax Liabilities IncomeTaxReconciliationInterestOnIncomeTaxLiabilities	2000000	USD
CY2019	cma	Effective Income Tax Rate Reconciliation Interest On Income Tax Liabilities EffectiveIncomeTaxRateReconciliationInterestOnIncomeTaxLiabilities	0.001
CY2018	cma	Income Tax Reconciliation Interest On Income Tax Liabilities IncomeTaxReconciliationInterestOnIncomeTaxLiabilities	-3000000	USD
CY2018	cma	Effective Income Tax Rate Reconciliation Interest On Income Tax Liabilities EffectiveIncomeTaxRateReconciliationInterestOnIncomeTaxLiabilities	-0.002
CY2017	cma	Income Tax Reconciliation Interest On Income Tax Liabilities IncomeTaxReconciliationInterestOnIncomeTaxLiabilities	4000000	USD
CY2017	cma	Effective Income Tax Rate Reconciliation Interest On Income Tax Liabilities EffectiveIncomeTaxRateReconciliationInterestOnIncomeTaxLiabilities	0.003
CY2019	cma	Effective Income Tax Rate Reconciliation Lease Termination Transactions Amount EffectiveIncomeTaxRateReconciliationLeaseTerminationTransactionsAmount	0	USD
CY2019	cma	Effective Income Tax Rate Reconciliation Lease Termination Transactions Percent EffectiveIncomeTaxRateReconciliationLeaseTerminationTransactionsPercent	0
CY2018	cma	Effective Income Tax Rate Reconciliation Lease Termination Transactions Amount EffectiveIncomeTaxRateReconciliationLeaseTerminationTransactionsAmount	0	USD
CY2018	cma	Effective Income Tax Rate Reconciliation Lease Termination Transactions Percent EffectiveIncomeTaxRateReconciliationLeaseTerminationTransactionsPercent	0
CY2017	cma	Effective Income Tax Rate Reconciliation Lease Termination Transactions Amount EffectiveIncomeTaxRateReconciliationLeaseTerminationTransactionsAmount	-2000000	USD
CY2017	cma	Effective Income Tax Rate Reconciliation Lease Termination Transactions Percent EffectiveIncomeTaxRateReconciliationLeaseTerminationTransactionsPercent	-0.002
CY2019	us-gaap	Income Tax Reconciliation Other Adjustments IncomeTaxReconciliationOtherAdjustments	4000000	USD
CY2019	us-gaap	Effective Income Tax Rate Reconciliation Other Adjustments EffectiveIncomeTaxRateReconciliationOtherAdjustments	0.002
CY2018	us-gaap	Income Tax Reconciliation Other Adjustments IncomeTaxReconciliationOtherAdjustments	2000000	USD
CY2018	us-gaap	Effective Income Tax Rate Reconciliation Other Adjustments EffectiveIncomeTaxRateReconciliationOtherAdjustments	0.001
CY2017	us-gaap	Income Tax Reconciliation Other Adjustments IncomeTaxReconciliationOtherAdjustments	0	USD
CY2017	us-gaap	Effective Income Tax Rate Reconciliation Other Adjustments EffectiveIncomeTaxRateReconciliationOtherAdjustments	0
CY2019	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	334000000	USD
CY2019	us-gaap	Effective Income Tax Rate Continuing Operations EffectiveIncomeTaxRateContinuingOperations	0.217
CY2018	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	300000000	USD
CY2018	us-gaap	Effective Income Tax Rate Continuing Operations EffectiveIncomeTaxRateContinuingOperations	0.195
CY2017	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	491000000	USD
CY2017	us-gaap	Effective Income Tax Rate Continuing Operations EffectiveIncomeTaxRateContinuingOperations	0.398
CY2019Q4	us-gaap	Unrecognized Tax Benefits Income Tax Penalties And Interest Accrued UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestAccrued	8000000	USD
CY2018Q4	us-gaap	Unrecognized Tax Benefits Income Tax Penalties And Interest Accrued UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestAccrued	7000000	USD
CY2018Q4	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	14000000	USD
CY2017Q4	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	10000000	USD
CY2016Q4	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	15000000	USD
CY2019	us-gaap	Unrecognized Tax Benefits Increases Resulting From Prior Period Tax Positions UnrecognizedTaxBenefitsIncreasesResultingFromPriorPeriodTaxPositions	4000000	USD
CY2018	us-gaap	Unrecognized Tax Benefits Increases Resulting From Prior Period Tax Positions UnrecognizedTaxBenefitsIncreasesResultingFromPriorPeriodTaxPositions	9000000	USD
CY2017	us-gaap	Unrecognized Tax Benefits Increases Resulting From Prior Period Tax Positions UnrecognizedTaxBenefitsIncreasesResultingFromPriorPeriodTaxPositions	4000000	USD
CY2019	us-gaap	Unrecognized Tax Benefits Decreases Resulting From Settlements With Taxing Authorities UnrecognizedTaxBenefitsDecreasesResultingFromSettlementsWithTaxingAuthorities	1000000	USD
CY2018	us-gaap	Unrecognized Tax Benefits Decreases Resulting From Settlements With Taxing Authorities UnrecognizedTaxBenefitsDecreasesResultingFromSettlementsWithTaxingAuthorities	4000000	USD
CY2017	us-gaap	Unrecognized Tax Benefits Decreases Resulting From Settlements With Taxing Authorities UnrecognizedTaxBenefitsDecreasesResultingFromSettlementsWithTaxingAuthorities	8000000	USD
CY2019	cma	Unrecognized Tax Benefits Decrease Resultingfrom Other Tax Position Changes UnrecognizedTaxBenefitsDecreaseResultingfromOtherTaxPositionChanges	0	USD
CY2018	cma	Unrecognized Tax Benefits Decrease Resultingfrom Other Tax Position Changes UnrecognizedTaxBenefitsDecreaseResultingfromOtherTaxPositionChanges	-1000000	USD
CY2017	cma	Unrecognized Tax Benefits Decrease Resultingfrom Other Tax Position Changes UnrecognizedTaxBenefitsDecreaseResultingfromOtherTaxPositionChanges	-1000000	USD
CY2019Q4	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	17000000	USD
CY2018Q4	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	14000000	USD
CY2017Q4	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	10000000	USD
CY2019Q4	us-gaap	Decrease In Unrecognized Tax Benefits Is Reasonably Possible DecreaseInUnrecognizedTaxBenefitsIsReasonablyPossible	5000000	USD
CY2019Q4	us-gaap	Unrecognized Tax Benefits That Would Impact Effective Tax Rate UnrecognizedTaxBenefitsThatWouldImpactEffectiveTaxRate	14000000	USD
CY2018Q4	us-gaap	Unrecognized Tax Benefits That Would Impact Effective Tax Rate UnrecognizedTaxBenefitsThatWouldImpactEffectiveTaxRate	11000000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Reserves And Accruals Provision For Loan Losses DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsProvisionForLoanLosses	134000000	USD
CY2018Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Reserves And Accruals Provision For Loan Losses DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsProvisionForLoanLosses	141000000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Compensation And Benefits Employee Compensation DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsEmployeeCompensation	61000000	USD
CY2018Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Compensation And Benefits Employee Compensation DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsEmployeeCompensation	68000000	USD
CY2019Q4	cma	Deferred Tax Assets Deferred Loan Orgination Fees And Costs DeferredTaxAssetsDeferredLoanOrginationFeesAndCosts	8000000	USD
CY2018Q4	cma	Deferred Tax Assets Deferred Loan Orgination Fees And Costs DeferredTaxAssetsDeferredLoanOrginationFeesAndCosts	9000000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Unrealized Losses On Availablefor Sale Securities Gross DeferredTaxAssetsUnrealizedLossesOnAvailableforSaleSecuritiesGross	0	USD
CY2018Q4	us-gaap	Deferred Tax Assets Unrealized Losses On Availablefor Sale Securities Gross DeferredTaxAssetsUnrealizedLossesOnAvailableforSaleSecuritiesGross	42000000	USD
CY2019Q4	cma	Deferred Tax Assets Operating Lease Liability DeferredTaxAssetsOperatingLeaseLiability	77000000	USD
CY2018Q4	cma	Deferred Tax Assets Operating Lease Liability DeferredTaxAssetsOperatingLeaseLiability	0	USD
CY2019Q4	us-gaap	Deferred Tax Assets Other DeferredTaxAssetsOther	49000000	USD
CY2018Q4	us-gaap	Deferred Tax Assets Other DeferredTaxAssetsOther	42000000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Gross DeferredTaxAssetsGross	329000000	USD
CY2018Q4	us-gaap	Deferred Tax Assets Gross DeferredTaxAssetsGross	302000000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Valuation Allowance DeferredTaxAssetsValuationAllowance	3000000	USD
CY2018Q4	us-gaap	Deferred Tax Assets Valuation Allowance DeferredTaxAssetsValuationAllowance	3000000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Net DeferredTaxAssetsNet	326000000	USD
CY2018Q4	us-gaap	Deferred Tax Assets Net DeferredTaxAssetsNet	299000000	USD
CY2019Q4	us-gaap	Deferred Tax Liabilities Leasing Arrangements DeferredTaxLiabilitiesLeasingArrangements	73000000	USD
CY2018Q4	us-gaap	Deferred Tax Liabilities Leasing Arrangements DeferredTaxLiabilitiesLeasingArrangements	74000000	USD
CY2019Q4	cma	Deferred Tax Liabilities Tax Deferred Income Compensationand Benefits Pensions DeferredTaxLiabilitiesTaxDeferredIncomeCompensationandBenefitsPensions	91000000	USD
CY2018Q4	cma	Deferred Tax Liabilities Tax Deferred Income Compensationand Benefits Pensions DeferredTaxLiabilitiesTaxDeferredIncomeCompensationandBenefitsPensions	41000000	USD
CY2019Q4	us-gaap	Deferred Tax Liabilities Property Plant And Equipment DeferredTaxLiabilitiesPropertyPlantAndEquipment	21000000	USD
CY2018Q4	us-gaap	Deferred Tax Liabilities Property Plant And Equipment DeferredTaxLiabilitiesPropertyPlantAndEquipment	18000000	USD
CY2019Q4	cma	Deferred Tax Liability Hedginggainsandlosses DeferredTaxLiabilityHedginggainsandlosses	-10000000	USD
CY2018Q4	cma	Deferred Tax Liability Hedginggainsandlosses DeferredTaxLiabilityHedginggainsandlosses	0	USD
CY2019Q4	cma	Deferred Tax Liability Lease Rightof Use Asset DeferredTaxLiabilityLeaseRightofUseAsset	-69000000	USD
CY2018Q4	cma	Deferred Tax Liability Lease Rightof Use Asset DeferredTaxLiabilityLeaseRightofUseAsset	0	USD
CY2019Q4	cma	Deferred Tax Liabilitynetunrealizedgainsoninvestmentsecuritiesavailableforsale DeferredTaxLiabilitynetunrealizedgainsoninvestmentsecuritiesavailableforsale	-20000000	USD
CY2018Q4	cma	Deferred Tax Liabilitynetunrealizedgainsoninvestmentsecuritiesavailableforsale DeferredTaxLiabilitynetunrealizedgainsoninvestmentsecuritiesavailableforsale	0	USD
CY2019Q4	us-gaap	Deferred Income Tax Liabilities DeferredIncomeTaxLiabilities	284000000	USD
CY2018Q4	us-gaap	Deferred Income Tax Liabilities DeferredIncomeTaxLiabilities	133000000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Liabilities Net DeferredTaxAssetsLiabilitiesNet	42000000	USD
CY2018Q4	us-gaap	Deferred Tax Assets Liabilities Net DeferredTaxAssetsLiabilitiesNet	166000000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Operating Loss Carryforwards State And Local DeferredTaxAssetsOperatingLossCarryforwardsStateAndLocal	3000000	USD
CY2018Q4	us-gaap	Deferred Tax Assets Operating Loss Carryforwards State And Local DeferredTaxAssetsOperatingLossCarryforwardsStateAndLocal	4000000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Valuation Allowance DeferredTaxAssetsValuationAllowance	3000000	USD
CY2018Q4	us-gaap	Loans And Leases Receivable Related Parties LoansAndLeasesReceivableRelatedParties	109000000	USD
CY2019Q4	us-gaap	Loans And Leases Receivable Related Parties LoansAndLeasesReceivableRelatedParties	74000000	USD
CY2019	us-gaap	Loans And Leases Receivable Related Parties Additions LoansAndLeasesReceivableRelatedPartiesAdditions	732000000	USD
CY2019	us-gaap	Loans And Leases Receivable Related Parties Proceeds LoansAndLeasesReceivableRelatedPartiesProceeds	767000000	USD
CY2019	cma	Average Reserve Requirement AverageReserveRequirement	586000000	USD
CY2018	cma	Average Reserve Requirement AverageReserveRequirement	599000000	USD
CY2019Q4	us-gaap	Statutory Accounting Practices Statutory Amount Available For Dividend Payments With Regulatory Approval StatutoryAccountingPracticesStatutoryAmountAvailableForDividendPaymentsWithRegulatoryApproval	98000000	USD
CY2019	cma	Cash Dividends Paid To Parent Company By Bank Subsidiaries CashDividendsPaidToParentCompanyByBankSubsidiaries	1200000000	USD
CY2018	cma	Cash Dividends Paid To Parent Company By Bank Subsidiaries CashDividendsPaidToParentCompanyByBankSubsidiaries	1100000000	USD
CY2017	cma	Cash Dividends Paid To Parent Company By Bank Subsidiaries CashDividendsPaidToParentCompanyByBankSubsidiaries	907000000	USD
CY2019Q4	us-gaap	Capital Required To Be Well Capitalized To Risk Weighted Assets CapitalRequiredToBeWellCapitalizedToRiskWeightedAssets	0.10
CY2019Q4	us-gaap	Tier One Risk Based Capital Required To Be Well Capitalized To Risk Weighted Assets TierOneRiskBasedCapitalRequiredToBeWellCapitalizedToRiskWeightedAssets	0.06
CY2019	us-gaap	Legal Fees LegalFees	15000000	USD
CY2018	us-gaap	Legal Fees LegalFees	17000000	USD
CY2017	us-gaap	Legal Fees LegalFees	15000000	USD
CY2019	cma	Number Of Major Business Segments NumberOfMajorBusinessSegments	3	segments
CY2019	cma	Number Of Major Business Segments NumberOfMajorBusinessSegments	3	segments
CY2019	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	2339000000	USD
CY2019	us-gaap	Provision For Loan And Lease Losses ProvisionForLoanAndLeaseLosses	74000000	USD
CY2019	us-gaap	Noninterest Income NoninterestIncome	1010000000	USD
CY2019	us-gaap	Noninterest Expense NoninterestExpense	1743000000	USD
CY2019	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	334000000	USD
CY2019	us-gaap	Profit Loss ProfitLoss	1198000000	USD
CY2019	cma	Net Credit Related Charge Offs NetCreditRelatedChargeOffs	107000000	USD
CY2019	cma	Segment Reporting Average Assets SegmentReportingAverageAssets	71488000000	USD
CY2019	cma	Average Balance During Period Loans And Leases Receivable Net Of Deferred Income AverageBalanceDuringPeriodLoansAndLeasesReceivableNetOfDeferredIncome	50511000000	USD
CY2019	cma	Average Balance During Period Deposits AverageBalanceDuringPeriodDeposits	55481000000	USD
CY2019	cma	Return On Average Assets ReturnOnAverageAssets	0.0168
CY2019	cma	Efficiency Ratio EfficiencyRatio	0.5182
CY2018	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	2352000000	USD
CY2018	us-gaap	Provision For Loan And Lease Losses ProvisionForLoanAndLeaseLosses	-1000000	USD
CY2018	us-gaap	Noninterest Income NoninterestIncome	976000000	USD
CY2018	us-gaap	Noninterest Expense NoninterestExpense	1794000000	USD
CY2018	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	300000000	USD
CY2018	us-gaap	Profit Loss ProfitLoss	1235000000	USD
CY2018	cma	Net Credit Related Charge Offs NetCreditRelatedChargeOffs	51000000	USD
CY2018	cma	Segment Reporting Average Assets SegmentReportingAverageAssets	70724000000	USD
CY2018	cma	Average Balance During Period Loans And Leases Receivable Net Of Deferred Income AverageBalanceDuringPeriodLoansAndLeasesReceivableNetOfDeferredIncome	48766000000	USD
CY2018	cma	Average Balance During Period Deposits AverageBalanceDuringPeriodDeposits	55935000000	USD
CY2018	cma	Return On Average Assets ReturnOnAverageAssets	0.0175
CY2018	cma	Efficiency Ratio EfficiencyRatio	0.5356
CY2017	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	2061000000	USD
CY2017	us-gaap	Provision For Loan And Lease Losses ProvisionForLoanAndLeaseLosses	74000000	USD
CY2017	us-gaap	Noninterest Income NoninterestIncome	1107000000	USD
CY2017	us-gaap	Noninterest Expense NoninterestExpense	1860000000	USD
CY2017	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	491000000	USD
CY2017	us-gaap	Profit Loss ProfitLoss	743000000	USD
CY2017	cma	Net Credit Related Charge Offs NetCreditRelatedChargeOffs	92000000	USD
CY2017	cma	Segment Reporting Average Assets SegmentReportingAverageAssets	71452000000	USD
CY2017	cma	Average Balance During Period Loans And Leases Receivable Net Of Deferred Income AverageBalanceDuringPeriodLoansAndLeasesReceivableNetOfDeferredIncome	48558000000	USD
CY2017	cma	Average Balance During Period Deposits AverageBalanceDuringPeriodDeposits	57258000000	USD
CY2017	cma	Return On Average Assets ReturnOnAverageAssets	0.0104
CY2017	cma	Efficiency Ratio EfficiencyRatio	0.5870
CY2019	cma	Number Of Geographic Markets NumberOfGeographicMarkets	3	markets
CY2019	cma	Number Of Geographic Markets NumberOfGeographicMarkets	3	markets
CY2019	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	2339000000	USD
CY2019	us-gaap	Provision For Loan And Lease Losses ProvisionForLoanAndLeaseLosses	74000000	USD
CY2019	us-gaap	Noninterest Income NoninterestIncome	1010000000	USD
CY2019	us-gaap	Noninterest Expense NoninterestExpense	1743000000	USD
CY2019	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	334000000	USD
CY2019	us-gaap	Profit Loss ProfitLoss	1198000000	USD
CY2019	cma	Net Credit Related Charge Offs NetCreditRelatedChargeOffs	107000000	USD
CY2019	cma	Segment Reporting Average Assets SegmentReportingAverageAssets	71488000000	USD
CY2019	cma	Average Balance During Period Loans And Leases Receivable Net Of Deferred Income AverageBalanceDuringPeriodLoansAndLeasesReceivableNetOfDeferredIncome	50511000000	USD
CY2019	cma	Average Balance During Period Deposits AverageBalanceDuringPeriodDeposits	55481000000	USD
CY2019	cma	Return On Average Assets ReturnOnAverageAssets	0.0168
CY2019	cma	Efficiency Ratio EfficiencyRatio	0.5182
CY2018	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	2352000000	USD
CY2018	us-gaap	Provision For Loan And Lease Losses ProvisionForLoanAndLeaseLosses	-1000000	USD
CY2018	us-gaap	Noninterest Income NoninterestIncome	976000000	USD
CY2018	us-gaap	Noninterest Expense NoninterestExpense	1794000000	USD
CY2018	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	300000000	USD
CY2018	us-gaap	Profit Loss ProfitLoss	1235000000	USD
CY2018	cma	Net Credit Related Charge Offs NetCreditRelatedChargeOffs	51000000	USD
CY2018	cma	Segment Reporting Average Assets SegmentReportingAverageAssets	70724000000	USD
CY2018	cma	Average Balance During Period Loans And Leases Receivable Net Of Deferred Income AverageBalanceDuringPeriodLoansAndLeasesReceivableNetOfDeferredIncome	48766000000	USD
CY2018	cma	Average Balance During Period Deposits AverageBalanceDuringPeriodDeposits	55935000000	USD
CY2018	cma	Return On Average Assets ReturnOnAverageAssets	0.0175
CY2018	cma	Efficiency Ratio EfficiencyRatio	0.5356
CY2017	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	2061000000	USD
CY2017	us-gaap	Provision For Loan And Lease Losses ProvisionForLoanAndLeaseLosses	74000000	USD
CY2017	us-gaap	Noninterest Income NoninterestIncome	1107000000	USD
CY2017	us-gaap	Noninterest Expense NoninterestExpense	1860000000	USD
CY2017	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	491000000	USD
CY2017	us-gaap	Profit Loss ProfitLoss	743000000	USD
CY2017	cma	Net Credit Related Charge Offs NetCreditRelatedChargeOffs	92000000	USD
CY2017	cma	Segment Reporting Average Assets SegmentReportingAverageAssets	71452000000	USD
CY2017	cma	Average Balance During Period Loans And Leases Receivable Net Of Deferred Income AverageBalanceDuringPeriodLoansAndLeasesReceivableNetOfDeferredIncome	48558000000	USD
CY2017	cma	Average Balance During Period Deposits AverageBalanceDuringPeriodDeposits	57258000000	USD
CY2017	cma	Return On Average Assets ReturnOnAverageAssets	0.0104
CY2017	cma	Efficiency Ratio EfficiencyRatio	0.5870
CY2019Q4	us-gaap	Interest And Dividend Income Operating InterestAndDividendIncomeOperating	659000000	USD
CY2019Q3	us-gaap	Interest And Dividend Income Operating InterestAndDividendIncomeOperating	711000000	USD
CY2019Q2	us-gaap	Interest And Dividend Income Operating InterestAndDividendIncomeOperating	727000000	USD
CY2019Q1	us-gaap	Interest And Dividend Income Operating InterestAndDividendIncomeOperating	710000000	USD
CY2019Q4	us-gaap	Interest Expense InterestExpense	115000000	USD
CY2019Q3	us-gaap	Interest Expense InterestExpense	125000000	USD
CY2019Q2	us-gaap	Interest Expense InterestExpense	124000000	USD
CY2019Q1	us-gaap	Interest Expense InterestExpense	104000000	USD
CY2019Q4	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	544000000	USD
CY2019Q3	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	586000000	USD
CY2019Q2	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	603000000	USD
CY2019Q1	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	606000000	USD
CY2019Q4	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	8000000	USD
CY2019Q3	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	35000000	USD
CY2019Q2	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	44000000	USD
CY2019Q1	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	-13000000	USD
CY2019Q4	us-gaap	Debt And Equity Securities Gain Loss DebtAndEquitySecuritiesGainLoss	1000000	USD
CY2019Q3	us-gaap	Debt And Equity Securities Gain Loss DebtAndEquitySecuritiesGainLoss	0	USD
CY2019Q2	us-gaap	Debt And Equity Securities Gain Loss DebtAndEquitySecuritiesGainLoss	0	USD
CY2019Q1	us-gaap	Debt And Equity Securities Gain Loss DebtAndEquitySecuritiesGainLoss	-8000000	USD
CY2019Q4	cma	Non Interest Income Excluding Net Securities Gains NonInterestIncomeExcludingNetSecuritiesGains	265000000	USD
CY2019Q3	cma	Non Interest Income Excluding Net Securities Gains NonInterestIncomeExcludingNetSecuritiesGains	256000000	USD
CY2019Q2	cma	Non Interest Income Excluding Net Securities Gains NonInterestIncomeExcludingNetSecuritiesGains	250000000	USD
CY2019Q1	cma	Non Interest Income Excluding Net Securities Gains NonInterestIncomeExcludingNetSecuritiesGains	246000000	USD
CY2019Q4	us-gaap	Noninterest Expense NoninterestExpense	451000000	USD
CY2019Q3	us-gaap	Noninterest Expense NoninterestExpense	435000000	USD
CY2019Q2	us-gaap	Noninterest Expense NoninterestExpense	424000000	USD
CY2019Q1	us-gaap	Noninterest Expense NoninterestExpense	433000000	USD
CY2019Q4	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	82000000	USD
CY2019Q3	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	80000000	USD
CY2019Q2	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	87000000	USD
CY2019Q1	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	85000000	USD
CY2019Q4	us-gaap	Profit Loss ProfitLoss	269000000	USD
CY2019Q3	us-gaap	Profit Loss ProfitLoss	292000000	USD
CY2019Q2	us-gaap	Profit Loss ProfitLoss	298000000	USD
CY2019Q1	us-gaap	Profit Loss ProfitLoss	339000000	USD
CY2019Q4	us-gaap	Undistributed Earnings Loss Allocated To Participating Securities Diluted UndistributedEarningsLossAllocatedToParticipatingSecuritiesDiluted	2000000	USD
CY2019Q3	us-gaap	Undistributed Earnings Loss Allocated To Participating Securities Diluted UndistributedEarningsLossAllocatedToParticipatingSecuritiesDiluted	2000000	USD
CY2019Q2	us-gaap	Undistributed Earnings Loss Allocated To Participating Securities Diluted UndistributedEarningsLossAllocatedToParticipatingSecuritiesDiluted	1000000	USD
CY2019Q1	us-gaap	Undistributed Earnings Loss Allocated To Participating Securities Diluted UndistributedEarningsLossAllocatedToParticipatingSecuritiesDiluted	2000000	USD
CY2019Q4	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	267000000	USD
CY2019Q3	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	290000000	USD
CY2019Q2	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	297000000	USD
CY2019Q1	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	337000000	USD
CY2019Q4	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.87
CY2019Q3	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.98
CY2019Q2	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.95
CY2019Q1	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	2.14
CY2019Q4	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.85
CY2018Q4	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	614000000	USD
CY2018Q3	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	599000000	USD
CY2019Q3	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.96
CY2019Q2	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.94
CY2019Q1	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	2.11
CY2019Q4	us-gaap	Comprehensive Income Net Of Tax Including Portion Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest	370000000	USD
CY2019Q3	us-gaap	Comprehensive Income Net Of Tax Including Portion Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest	338000000	USD
CY2019Q2	us-gaap	Comprehensive Income Net Of Tax Including Portion Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest	429000000	USD
CY2019Q1	us-gaap	Comprehensive Income Net Of Tax Including Portion Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest	435000000	USD
CY2018Q4	us-gaap	Interest And Dividend Income Operating InterestAndDividendIncomeOperating	704000000	USD
CY2018Q3	us-gaap	Interest And Dividend Income Operating InterestAndDividendIncomeOperating	675000000	USD
CY2017Q4	us-gaap	Interest And Dividend Income Operating InterestAndDividendIncomeOperating	650000000	USD
CY2018Q1	us-gaap	Interest And Dividend Income Operating InterestAndDividendIncomeOperating	590000000	USD
CY2018Q4	us-gaap	Interest Expense InterestExpense	90000000	USD
CY2018Q3	us-gaap	Interest Expense InterestExpense	76000000	USD
CY2017Q4	us-gaap	Interest Expense InterestExpense	60000000	USD
CY2018Q1	us-gaap	Interest Expense InterestExpense	41000000	USD
CY2017Q4	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	590000000	USD
CY2018Q1	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	549000000	USD
CY2018Q4	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	16000000	USD
CY2018Q3	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	0	USD
CY2017Q4	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	-29000000	USD
CY2018Q1	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	12000000	USD
CY2018Q4	us-gaap	Debt And Equity Securities Gain Loss DebtAndEquitySecuritiesGainLoss	0	USD
CY2018Q3	us-gaap	Debt And Equity Securities Gain Loss DebtAndEquitySecuritiesGainLoss	-20000000	USD
CY2017Q4	us-gaap	Debt And Equity Securities Gain Loss DebtAndEquitySecuritiesGainLoss	0	USD
CY2018Q1	us-gaap	Debt And Equity Securities Gain Loss DebtAndEquitySecuritiesGainLoss	1000000	USD
CY2018Q4	cma	Non Interest Income Excluding Net Securities Gains NonInterestIncomeExcludingNetSecuritiesGains	250000000	USD
CY2018Q3	cma	Non Interest Income Excluding Net Securities Gains NonInterestIncomeExcludingNetSecuritiesGains	254000000	USD
CY2017Q4	cma	Non Interest Income Excluding Net Securities Gains NonInterestIncomeExcludingNetSecuritiesGains	248000000	USD
CY2018Q1	cma	Non Interest Income Excluding Net Securities Gains NonInterestIncomeExcludingNetSecuritiesGains	243000000	USD
CY2018Q4	us-gaap	Noninterest Expense NoninterestExpense	448000000	USD
CY2018Q3	us-gaap	Noninterest Expense NoninterestExpense	452000000	USD
CY2017Q4	us-gaap	Noninterest Expense NoninterestExpense	448000000	USD
CY2018Q1	us-gaap	Noninterest Expense NoninterestExpense	446000000	USD
CY2018Q4	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	90000000	USD
CY2018Q3	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	63000000	USD
CY2017Q4	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	93000000	USD
CY2018Q1	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	54000000	USD
CY2018Q4	us-gaap	Profit Loss ProfitLoss	310000000	USD
CY2018Q1	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.62
CY2018Q4	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.88
CY2018Q3	us-gaap	Profit Loss ProfitLoss	318000000	USD
CY2017Q4	us-gaap	Profit Loss ProfitLoss	326000000	USD
CY2018Q1	us-gaap	Profit Loss ProfitLoss	281000000	USD
CY2018Q4	us-gaap	Undistributed Earnings Loss Allocated To Participating Securities Diluted UndistributedEarningsLossAllocatedToParticipatingSecuritiesDiluted	2000000	USD
CY2018Q3	us-gaap	Undistributed Earnings Loss Allocated To Participating Securities Diluted UndistributedEarningsLossAllocatedToParticipatingSecuritiesDiluted	2000000	USD
CY2017Q4	us-gaap	Undistributed Earnings Loss Allocated To Participating Securities Diluted UndistributedEarningsLossAllocatedToParticipatingSecuritiesDiluted	2000000	USD
CY2018Q1	us-gaap	Undistributed Earnings Loss Allocated To Participating Securities Diluted UndistributedEarningsLossAllocatedToParticipatingSecuritiesDiluted	2000000	USD
CY2018Q4	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	308000000	USD
CY2018Q3	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	316000000	USD
CY2017Q4	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	324000000	USD
CY2018Q1	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	279000000	USD
CY2018Q4	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.91
CY2018Q3	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.89
CY2017Q4	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.90
CY2018Q3	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.86
CY2017Q4	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.87
CY2018Q1	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.59
CY2018Q4	us-gaap	Comprehensive Income Net Of Tax Including Portion Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest	312000000	USD
CY2018Q3	us-gaap	Comprehensive Income Net Of Tax Including Portion Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest	296000000	USD
CY2017Q4	us-gaap	Comprehensive Income Net Of Tax Including Portion Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest	290000000	USD
CY2018Q1	us-gaap	Comprehensive Income Net Of Tax Including Portion Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest	178000000	USD
CY2019	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	749000000	USD
CY2019	cma	Othersourcesofnoninterestincome Othersourcesofnoninterestincome	261000000	USD
CY2019	us-gaap	Noninterest Income NoninterestIncome	1010000000	USD
CY2018	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	755000000	USD
CY2018	cma	Othersourcesofnoninterestincome Othersourcesofnoninterestincome	221000000	USD
CY2018	us-gaap	Noninterest Income NoninterestIncome	976000000	USD
CY2017	cma	Card Fees CardFees	333000000	USD
CY2017	cma	Fiduciaryincome Fiduciaryincome	198000000	USD
CY2017	cma	Servicechargesondepositaccounts Servicechargesondepositaccounts	227000000	USD
CY2017	cma	Commercial Lending Fees CommercialLendingFees	85000000	USD
CY2017	cma	Letter Of Credit Fees LetterOfCreditFees	45000000	USD
CY2017	us-gaap	Bank Owned Life Insurance Income BankOwnedLifeInsuranceIncome	43000000	USD
CY2017	us-gaap	Foreign Currency Transaction Gain Loss Before Tax ForeignCurrencyTransactionGainLossBeforeTax	45000000	USD
CY2017	us-gaap	Brokerage Commissions Revenue BrokerageCommissionsRevenue	23000000	USD
CY2017	cma	Othersourcesofnoninterestincome Othersourcesofnoninterestincome	108000000	USD
CY2017	us-gaap	Noninterest Income NoninterestIncome	1107000000	USD
CY2019	us-gaap	Lease Cost LeaseCost	81000000	USD
CY2019	us-gaap	Operating Lease Expense OperatingLeaseExpense	64000000	USD
CY2019	us-gaap	Variable Lease Cost VariableLeaseCost	19000000	USD
CY2019	us-gaap	Sublease Income SubleaseIncome	2000000	USD
CY2019Q4	us-gaap	Operating Lease Right Of Use Asset OperatingLeaseRightOfUseAsset	329000000	USD
CY2019Q4	us-gaap	Operating Lease Liability OperatingLeaseLiability	367000000	USD
CY2019Q4	us-gaap	Lessee Operating Lease Discount Rate LesseeOperatingLeaseDiscountRate	0.0378
CY2019	cma	New Rightof Use Assets NewRightofUseAssets	49000000	USD
CY2019	us-gaap	Operating Lease Payments OperatingLeasePayments	67000000	USD
CY2019Q4	us-gaap	Lessee Operating Lease Liability Payments Remainder Of Fiscal Year LesseeOperatingLeaseLiabilityPaymentsRemainderOfFiscalYear	60000000	USD
CY2019Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Two LesseeOperatingLeaseLiabilityPaymentsDueYearTwo	62000000	USD
CY2019Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Three LesseeOperatingLeaseLiabilityPaymentsDueYearThree	53000000	USD
CY2019Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Four LesseeOperatingLeaseLiabilityPaymentsDueYearFour	46000000	USD
CY2019Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Five LesseeOperatingLeaseLiabilityPaymentsDueYearFive	42000000	USD
CY2019Q4	us-gaap	Lessee Operating Lease Liability Payments Due After Year Five LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive	175000000	USD
CY2019Q4	us-gaap	Lessee Operating Lease Liability Payments Due LesseeOperatingLeaseLiabilityPaymentsDue	438000000	USD
CY2019	cma	Operatingleaseimputedinterest Operatingleaseimputedinterest	-71000000	USD
CY2019Q4	us-gaap	Operating Lease Liability OperatingLeaseLiability	367000000	USD
CY2019	us-gaap	Sales Type Lease Lease Income SalesTypeLeaseLeaseIncome	14000000	USD
CY2019Q4	us-gaap	Sales Type And Direct Financing Leases Lease Receivable SalesTypeAndDirectFinancingLeasesLeaseReceivable	369000000	USD
CY2019Q4	us-gaap	Sales Type And Direct Financing Leases Lease Receivable Payments To Be Received Remainder Of Fiscal Year SalesTypeAndDirectFinancingLeasesLeaseReceivablePaymentsToBeReceivedRemainderOfFiscalYear	66000000	USD
CY2019Q4	us-gaap	Sales Type And Direct Financing Leases Lease Receivable Payments To Be Received Two Years SalesTypeAndDirectFinancingLeasesLeaseReceivablePaymentsToBeReceivedTwoYears	54000000	USD
CY2019Q4	us-gaap	Sales Type And Direct Financing Leases Lease Receivable Payments To Be Received Three Years SalesTypeAndDirectFinancingLeasesLeaseReceivablePaymentsToBeReceivedThreeYears	90000000	USD
CY2019Q4	us-gaap	Sales Type And Direct Financing Leases Lease Receivable Payments To Be Received Four Years SalesTypeAndDirectFinancingLeasesLeaseReceivablePaymentsToBeReceivedFourYears	45000000	USD
CY2019Q4	us-gaap	Sales Type And Direct Financing Leases Lease Receivable Payments To Be Received Five Years SalesTypeAndDirectFinancingLeasesLeaseReceivablePaymentsToBeReceivedFiveYears	40000000	USD
CY2019Q4	us-gaap	Sales Type And Direct Financing Leases Lease Receivable Payments To Be Received Thereafter SalesTypeAndDirectFinancingLeasesLeaseReceivablePaymentsToBeReceivedThereafter	31000000	USD
CY2019Q4	us-gaap	Sales Type And Direct Financing Leases Lease Receivable Payments To Be Received SalesTypeAndDirectFinancingLeasesLeaseReceivablePaymentsToBeReceived	326000000	USD
CY2019Q4	cma	Sales Typeand Direct Financing Leases Unguaranteed Residual Asset SalesTypeandDirectFinancingLeasesUnguaranteedResidualAsset	64000000	USD
CY2019Q4	us-gaap	Deferred Discounts Finance Charges And Interest Included In Receivables DeferredDiscountsFinanceChargesAndInterestIncludedInReceivables	21000000	USD
CY2019Q4	us-gaap	Sales Type And Direct Financing Leases Lease Receivable SalesTypeAndDirectFinancingLeasesLeaseReceivable	369000000	USD

Files In Submission

Name	View Source	Status
0000028412-20-000034-index-headers.html	Edgar Link	pending
0000028412-20-000034-index.html	Edgar Link	pending
0000028412-20-000034.txt	Edgar Link	pending
0000028412-20-000034-xbrl.zip	Edgar Link	pending
a201910k.htm	Edgar Link	pending
a201910kex1018a.htm	Edgar Link	pending
a201910kex1019a.htm	Edgar Link	pending
a201910kex1020a.htm	Edgar Link	pending
a201910kex1022.htm	Edgar Link	pending
a201910kex21.htm	Edgar Link	pending
a201910kex231.htm	Edgar Link	pending
a201910kex311.htm	Edgar Link	pending
a201910kex312.htm	Edgar Link	pending
a201910kex32.htm	Edgar Link	pending
a201910kex42.htm	Edgar Link	pending
a201910k_htm.xml	Edgar Link	completed
a2019ye5yearcomparison.jpg	Edgar Link	pending
cma-20191231.xsd	Edgar Link	pending
cma-20191231_cal.xml	Edgar Link	unprocessable
cma-20191231_def.xml	Edgar Link	unprocessable
cma-20191231_lab.xml	Edgar Link	unprocessable
cma-20191231_pre.xml	Edgar Link	unprocessable
FilingSummary.xml	Edgar Link	unprocessable
Financial_Report.xlsx	Edgar Link	pending
MetaLinks.json	Edgar Link	pending
R1.htm	Edgar Link	pending
R10.htm	Edgar Link	pending
R100.htm	Edgar Link	pending
R101.htm	Edgar Link	pending
R102.htm	Edgar Link	pending
R103.htm	Edgar Link	pending
R104.htm	Edgar Link	pending
R105.htm	Edgar Link	pending
R106.htm	Edgar Link	pending
R107.htm	Edgar Link	pending
R108.htm	Edgar Link	pending
R109.htm	Edgar Link	pending
R11.htm	Edgar Link	pending
R110.htm	Edgar Link	pending
R111.htm	Edgar Link	pending
R112.htm	Edgar Link	pending
R113.htm	Edgar Link	pending
R114.htm	Edgar Link	pending
R115.htm	Edgar Link	pending
R116.htm	Edgar Link	pending
R117.htm	Edgar Link	pending
R118.htm	Edgar Link	pending
R119.htm	Edgar Link	pending
R12.htm	Edgar Link	pending
R120.htm	Edgar Link	pending
R121.htm	Edgar Link	pending
R122.htm	Edgar Link	pending
R123.htm	Edgar Link	pending
R124.htm	Edgar Link	pending
R125.htm	Edgar Link	pending
R126.htm	Edgar Link	pending
R127.htm	Edgar Link	pending
R128.htm	Edgar Link	pending
R129.htm	Edgar Link	pending
R13.htm	Edgar Link	pending
R130.htm	Edgar Link	pending
R131.htm	Edgar Link	pending
R132.htm	Edgar Link	pending
R133.htm	Edgar Link	pending
R134.htm	Edgar Link	pending
R135.htm	Edgar Link	pending
R136.htm	Edgar Link	pending
R137.htm	Edgar Link	pending
R138.htm	Edgar Link	pending
R139.htm	Edgar Link	pending
R14.htm	Edgar Link	pending
R140.htm	Edgar Link	pending
R141.htm	Edgar Link	pending
R142.htm	Edgar Link	pending
R143.htm	Edgar Link	pending
R15.htm	Edgar Link	pending
R16.htm	Edgar Link	pending
R17.htm	Edgar Link	pending
R18.htm	Edgar Link	pending
R19.htm	Edgar Link	pending
R2.htm	Edgar Link	pending
R20.htm	Edgar Link	pending
R21.htm	Edgar Link	pending
R22.htm	Edgar Link	pending
R23.htm	Edgar Link	pending
R24.htm	Edgar Link	pending
R25.htm	Edgar Link	pending
R26.htm	Edgar Link	pending
R27.htm	Edgar Link	pending
R28.htm	Edgar Link	pending
R29.htm	Edgar Link	pending
R3.htm	Edgar Link	pending
R30.htm	Edgar Link	pending
R31.htm	Edgar Link	pending
R32.htm	Edgar Link	pending
R33.htm	Edgar Link	pending
R34.htm	Edgar Link	pending
R35.htm	Edgar Link	pending
R36.htm	Edgar Link	pending
R37.htm	Edgar Link	pending
R38.htm	Edgar Link	pending
R39.htm	Edgar Link	pending
R4.htm	Edgar Link	pending
R40.htm	Edgar Link	pending
R41.htm	Edgar Link	pending
R42.htm	Edgar Link	pending
R43.htm	Edgar Link	pending
R44.htm	Edgar Link	pending
R45.htm	Edgar Link	pending
R46.htm	Edgar Link	pending
R47.htm	Edgar Link	pending
R48.htm	Edgar Link	pending
R49.htm	Edgar Link	pending
R5.htm	Edgar Link	pending
R50.htm	Edgar Link	pending
R51.htm	Edgar Link	pending
R52.htm	Edgar Link	pending
R53.htm	Edgar Link	pending
R54.htm	Edgar Link	pending
R55.htm	Edgar Link	pending
R56.htm	Edgar Link	pending
R57.htm	Edgar Link	pending
R58.htm	Edgar Link	pending
R59.htm	Edgar Link	pending
R6.htm	Edgar Link	pending
R60.htm	Edgar Link	pending
R61.htm	Edgar Link	pending
R62.htm	Edgar Link	pending
R63.htm	Edgar Link	pending
R64.htm	Edgar Link	pending
R65.htm	Edgar Link	pending
R66.htm	Edgar Link	pending
R67.htm	Edgar Link	pending
R68.htm	Edgar Link	pending
R69.htm	Edgar Link	pending
R7.htm	Edgar Link	pending
R70.htm	Edgar Link	pending
R71.htm	Edgar Link	pending
R72.htm	Edgar Link	pending
R73.htm	Edgar Link	pending
R74.htm	Edgar Link	pending
R75.htm	Edgar Link	pending
R76.htm	Edgar Link	pending
R77.htm	Edgar Link	pending
R78.htm	Edgar Link	pending
R79.htm	Edgar Link	pending
R8.htm	Edgar Link	pending
R80.htm	Edgar Link	pending
R81.htm	Edgar Link	pending
R82.htm	Edgar Link	pending
R83.htm	Edgar Link	pending
R84.htm	Edgar Link	pending
R85.htm	Edgar Link	pending
R86.htm	Edgar Link	pending
R87.htm	Edgar Link	pending
R88.htm	Edgar Link	pending
R89.htm	Edgar Link	pending
R9.htm	Edgar Link	pending
R90.htm	Edgar Link	pending
R91.htm	Edgar Link	pending
R92.htm	Edgar Link	pending
R93.htm	Edgar Link	pending
R94.htm	Edgar Link	pending
R95.htm	Edgar Link	pending
R96.htm	Edgar Link	pending
R97.htm	Edgar Link	pending
R98.htm	Edgar Link	pending
R99.htm	Edgar Link	pending
report.css	Edgar Link	pending
Show.js	Edgar Link	pending

Create your account

Find Stocks Worth Researching

Deeply Understand Businesses

Value Businesses Intelligently

$CMA
COMERICA INC /NEW/ Stock $cma

2019 Form 10-K Financial Statement

#000002841220000034 Filed on February 11, 2020

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$CMA COMERICA INC /NEW/ Stock $cma

2019 Form 10-K Financial Statement

#000002841220000034 Filed on February 11, 2020

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$CMA
COMERICA INC /NEW/ Stock $cma