Derivative Instruments and Hedging Activities - Effects of Fair Value and Cash Flow Hedge Accounting (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2022	Mar. 31, 2021
Derivative Instruments, Gain (Loss) [Line Items]
Interest and dividend income, securities	$ 402	$ 391
Interest and fee income, loans	6,367	5,854
Interest and dividend income, other	15	16
Deposits	(218)	(269)
Securitized debt obligations	(29)	(32)
Senior and subordinated notes	(131)	(129)
Non-interest income	343	122
Amortization expense (benefit)	(17)	(22)
Loss (net after-tax) recorded in AOCI related to derivatives designated as cash flow hedges expected to be reclassified to earnings over the next 12 months	$ (65)
Maximum length of time over which forecasted transactions were hedged, years	6 years
Non interest income - Other
Derivative Instruments, Gain (Loss) [Line Items]
Realized losses (gains) on foreign exchange contracts reclassified from AOCI	$ 13	(85)
Fair value hedges \| Interest income - Investment securities
Derivative Instruments, Gain (Loss) [Line Items]
Net income (expense) recognized on fair value hedges	(34)	(30)
Fair value hedges \| Interest income - Loans
Derivative Instruments, Gain (Loss) [Line Items]
Net income (expense) recognized on fair value hedges	0	0
Fair value hedges \| Interest income - Other
Derivative Instruments, Gain (Loss) [Line Items]
Net income (expense) recognized on fair value hedges	0	0
Fair value hedges \| Interest expense - Deposits
Derivative Instruments, Gain (Loss) [Line Items]
Net income (expense) recognized on fair value hedges	21	36
Fair value hedges \| Interest expense - Securitized Debt Obligation
Derivative Instruments, Gain (Loss) [Line Items]
Net income (expense) recognized on fair value hedges	25	28
Fair value hedges \| Interest expense - Senior and Subordinated Debt
Derivative Instruments, Gain (Loss) [Line Items]
Net income (expense) recognized on fair value hedges	77	93
Fair value hedges \| Non interest income - Other
Derivative Instruments, Gain (Loss) [Line Items]
Net income (expense) recognized on fair value hedges	0	0
Fair value hedges \| Interest rate contracts \| Interest income - Investment securities
Derivative Instruments, Gain (Loss) [Line Items]
Interest recognized on derivatives	(8)	(25)
Gains (losses) recognized on derivatives	175	100
Gains (losses) recognized on hedged items	(201)	(105)
Gain (Loss) from Components Excluded from Assessment of Fair Value Hedge Effectiveness, Net	0	0
Fair value hedges \| Interest rate contracts \| Interest income - Loans
Derivative Instruments, Gain (Loss) [Line Items]
Interest recognized on derivatives	0	0
Gains (losses) recognized on derivatives	0	0
Gains (losses) recognized on hedged items	0	0
Gain (Loss) from Components Excluded from Assessment of Fair Value Hedge Effectiveness, Net	0	0
Fair value hedges \| Interest rate contracts \| Interest income - Other
Derivative Instruments, Gain (Loss) [Line Items]
Interest recognized on derivatives	0	0
Gains (losses) recognized on derivatives	0	0
Gains (losses) recognized on hedged items	0	0
Gain (Loss) from Components Excluded from Assessment of Fair Value Hedge Effectiveness, Net	0	0
Fair value hedges \| Interest rate contracts \| Interest expense - Deposits
Derivative Instruments, Gain (Loss) [Line Items]
Interest recognized on derivatives	21	36
Gains (losses) recognized on derivatives	(115)	(58)
Gains (losses) recognized on hedged items	115	58
Gain (Loss) from Components Excluded from Assessment of Fair Value Hedge Effectiveness, Net	0	0
Fair value hedges \| Interest rate contracts \| Interest expense - Securitized Debt Obligation
Derivative Instruments, Gain (Loss) [Line Items]
Interest recognized on derivatives	27	33
Gains (losses) recognized on derivatives	(305)	(80)
Gains (losses) recognized on hedged items	303	75
Gain (Loss) from Components Excluded from Assessment of Fair Value Hedge Effectiveness, Net	0	0
Fair value hedges \| Interest rate contracts \| Interest expense - Senior and Subordinated Debt
Derivative Instruments, Gain (Loss) [Line Items]
Interest recognized on derivatives	38	62
Gains (losses) recognized on derivatives	(856)	(336)
Gains (losses) recognized on hedged items	896	368
Gain (Loss) from Components Excluded from Assessment of Fair Value Hedge Effectiveness, Net	(1)	(1)
Fair value hedges \| Interest rate contracts \| Non interest income - Other
Derivative Instruments, Gain (Loss) [Line Items]
Interest recognized on derivatives	0	0
Gains (losses) recognized on derivatives	(38)	(61)
Gains (losses) recognized on hedged items	38	61
Gain (Loss) from Components Excluded from Assessment of Fair Value Hedge Effectiveness, Net	0	0
Cash flow hedges \| Interest income - Investment securities
Derivative Instruments, Gain (Loss) [Line Items]
Net income recognized on cash flow hedges	0	9
Cash flow hedges \| Interest income - Loans
Derivative Instruments, Gain (Loss) [Line Items]
Net income recognized on cash flow hedges	127	226
Cash flow hedges \| Interest income - Other
Derivative Instruments, Gain (Loss) [Line Items]
Net income recognized on cash flow hedges	0	1
Cash flow hedges \| Interest expense - Deposits
Derivative Instruments, Gain (Loss) [Line Items]
Net income recognized on cash flow hedges	0	0
Cash flow hedges \| Interest expense - Securitized Debt Obligation
Derivative Instruments, Gain (Loss) [Line Items]
Net income recognized on cash flow hedges	0	0
Cash flow hedges \| Interest expense - Senior and Subordinated Debt
Derivative Instruments, Gain (Loss) [Line Items]
Net income recognized on cash flow hedges	0	0
Cash flow hedges \| Non interest income - Other
Derivative Instruments, Gain (Loss) [Line Items]
Net income recognized on cash flow hedges	0	0
Cash flow hedges \| Interest rate contracts \| Interest income - Investment securities
Derivative Instruments, Gain (Loss) [Line Items]
Reclassification adjustment from AOCI on derivatives, net of tax	0	9
Cash flow hedges \| Interest rate contracts \| Interest income - Loans
Derivative Instruments, Gain (Loss) [Line Items]
Reclassification adjustment from AOCI on derivatives, net of tax	127	226
Cash flow hedges \| Interest rate contracts \| Interest income - Other
Derivative Instruments, Gain (Loss) [Line Items]
Reclassification adjustment from AOCI on derivatives, net of tax	0	0
Cash flow hedges \| Interest rate contracts \| Interest expense - Deposits
Derivative Instruments, Gain (Loss) [Line Items]
Reclassification adjustment from AOCI on derivatives, net of tax	0	0
Cash flow hedges \| Interest rate contracts \| Interest expense - Securitized Debt Obligation
Derivative Instruments, Gain (Loss) [Line Items]
Reclassification adjustment from AOCI on derivatives, net of tax	0	0
Cash flow hedges \| Interest rate contracts \| Interest expense - Senior and Subordinated Debt
Derivative Instruments, Gain (Loss) [Line Items]
Reclassification adjustment from AOCI on derivatives, net of tax	0	0
Cash flow hedges \| Interest rate contracts \| Non interest income - Other
Derivative Instruments, Gain (Loss) [Line Items]
Reclassification adjustment from AOCI on derivatives, net of tax	0	0
Cash flow hedges \| Foreign exchange contracts \| Interest income - Investment securities
Derivative Instruments, Gain (Loss) [Line Items]
Reclassification adjustment from AOCI on derivatives, net of tax	0	0
Cash flow hedges \| Foreign exchange contracts \| Interest income - Loans
Derivative Instruments, Gain (Loss) [Line Items]
Reclassification adjustment from AOCI on derivatives, net of tax	0	0
Cash flow hedges \| Foreign exchange contracts \| Interest income - Other
Derivative Instruments, Gain (Loss) [Line Items]
Reclassification adjustment from AOCI on derivatives, net of tax	0	1
Cash flow hedges \| Foreign exchange contracts \| Interest expense - Deposits
Derivative Instruments, Gain (Loss) [Line Items]
Reclassification adjustment from AOCI on derivatives, net of tax	0	0
Cash flow hedges \| Foreign exchange contracts \| Interest expense - Securitized Debt Obligation
Derivative Instruments, Gain (Loss) [Line Items]
Reclassification adjustment from AOCI on derivatives, net of tax	0	0
Cash flow hedges \| Foreign exchange contracts \| Interest expense - Senior and Subordinated Debt
Derivative Instruments, Gain (Loss) [Line Items]
Reclassification adjustment from AOCI on derivatives, net of tax	0	0
Cash flow hedges \| Foreign exchange contracts \| Non interest income - Other
Derivative Instruments, Gain (Loss) [Line Items]
Reclassification adjustment from AOCI on derivatives, net of tax	$ 0	$ 0

Amortization of Basis Adjustment on Discontinued Hedges

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Total amount of gain (loss) derived from cash flow hedges recognized in earnings in the period

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Realized Gains (Losses) On Foreign Exchange Contracts Reclassified From AOCI

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The estimated net amount of existing gains or losses on cash flow hedges at the reporting date expected to be reclassified to earnings within the next 12 months.

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Amount of gain (loss) from the increase (decrease) in fair value of derivative and nonderivative instruments designated as fair value hedging instruments recognized in the income statement.

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Net gain (loss) relating to components of the gain (loss) on the fair value hedging instrument excluded from the assessment of fair value hedge effectiveness. Recognized in earnings.

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Total amount of gain (loss) derived from fair value hedges recognized in earnings in the period.

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Amount of operating dividend and interest income, including amortization and accretion of premiums and discounts, on securities.

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The aggregate interest and fee income generated by: (1) loans the Entity has positive intent and ability to hold for the foreseeable future, or until maturity or payoff, including commercial and consumer loans, whether domestic or foreign, which may consist of: (a) industrial and agricultural; (b) real estate; and (c) real estate construction loans; (d) trade financing; (e) lease financing; (f) home equity lines-of-credit; (g) automobile and other vehicle loans; and (h) credit card and other revolving-type loans and (2) loans and leases held-for-sale which may include mortgage loans, direct financing, and sales-type leases.

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Amount, after discount, accretion and premium amortization, of interest income and dividend income classified as other.

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