Derivative Instruments and Hedging Activities - Effects of Fair Value and Cash Flow Hedge Accounting (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Interest income:
Investment Securities	$ 700	$ 639	$ 1,387	$ 1,254
Loans, Including Loans Held for Sale	9,993	9,057	19,913	17,780
Other	587	470	1,157	886
Interest-bearing Deposits	(2,874)	(2,277)	(5,686)	(4,133)
Securitized Debt Obligations	(258)	(236)	(519)	(447)
Senior and Subordinated Notes	(591)	(528)	(1,197)	(1,017)
Non-interest income (expense)	252	275	559	474
Amortization expense (benefit)	(18)	(21)	(41)	(36)
Non-Interest Income, Other
Interest income:
Realized gain (loss) on foreign exchange contracts reclassified from AOCI	(19)	(22)	55	(30)
Fair value hedges \| Investment Securities
Interest income:
Net income (expense) recognized on fair value hedges	24	20	51	35
Fair value hedges \| Loans, Including Loans Held for Sale
Interest income:
Net income (expense) recognized on fair value hedges	0	0	0	0
Fair value hedges \| Other
Interest income:
Net income (expense) recognized on fair value hedges	0	0	0	0
Fair value hedges \| Interest-bearing Deposits
Interest income:
Net income (expense) recognized on fair value hedges	(98)	(97)	(205)	(177)
Fair value hedges \| Securitized Debt Obligations
Interest income:
Net income (expense) recognized on fair value hedges	(119)	(101)	(237)	(186)
Fair value hedges \| Senior and Subordinated Notes
Interest income:
Net income (expense) recognized on fair value hedges	(210)	(218)	(438)	(407)
Fair value hedges \| Non-Interest Income, Other
Interest income:
Net income (expense) recognized on fair value hedges	0	0	0	0
Fair value hedges \| Interest rate contracts: \| Investment Securities
Interest income:
Interest recognized on derivatives	41	38	86	71
Gains (losses) recognized on derivatives	(14)	29	7	(20)
Gains (losses) recognized on hedged items	(3)	(47)	(42)	(16)
Excluded component of fair value hedges	0	0	0	0
Fair value hedges \| Interest rate contracts: \| Loans, Including Loans Held for Sale
Interest income:
Interest recognized on derivatives	0	0	0	0
Gains (losses) recognized on derivatives	0	0	0	0
Gains (losses) recognized on hedged items	0	0	0	0
Excluded component of fair value hedges	0	0	0	0
Fair value hedges \| Interest rate contracts: \| Other
Interest income:
Interest recognized on derivatives	0	0	0	0
Gains (losses) recognized on derivatives	0	0	0	0
Gains (losses) recognized on hedged items	0	0	0	0
Excluded component of fair value hedges	0	0	0	0
Fair value hedges \| Interest rate contracts: \| Interest-bearing Deposits
Interest income:
Interest recognized on derivatives	(97)	(96)	(204)	(174)
Gains (losses) recognized on derivatives	37	(224)	(34)	(46)
Gains (losses) recognized on hedged items	(38)	223	33	43
Excluded component of fair value hedges	0	0	0	0
Fair value hedges \| Interest rate contracts: \| Securitized Debt Obligations
Interest income:
Interest recognized on derivatives	(119)	(101)	(237)	(185)
Gains (losses) recognized on derivatives	70	(162)	51	(14)
Gains (losses) recognized on hedged items	(70)	162	(51)	13
Excluded component of fair value hedges	0	0	0	0
Fair value hedges \| Interest rate contracts: \| Senior and Subordinated Notes
Interest income:
Interest recognized on derivatives	(256)	(259)	(523)	(479)
Gains (losses) recognized on derivatives	48	(389)	(268)	(2)
Gains (losses) recognized on hedged items	(10)	430	346	75
Excluded component of fair value hedges	8	0	7	(1)
Fair value hedges \| Interest rate contracts: \| Non-Interest Income, Other
Interest income:
Interest recognized on derivatives	0	0	0	0
Gains (losses) recognized on derivatives	(8)	8	(39)	25
Gains (losses) recognized on hedged items	8	(8)	39	(25)
Excluded component of fair value hedges	0	0	0	0
Cash flow hedges \| Investment Securities
Interest income:
Net income (expense) recognized on cash flow hedges	0	0	0	0
Cash flow hedges \| Loans, Including Loans Held for Sale
Interest income:
Net income (expense) recognized on cash flow hedges	(313)	(297)	(622)	(559)
Cash flow hedges \| Other
Interest income:
Net income (expense) recognized on cash flow hedges	3	3	5	6
Cash flow hedges \| Interest-bearing Deposits
Interest income:
Net income (expense) recognized on cash flow hedges	0	0	0	0
Cash flow hedges \| Securitized Debt Obligations
Interest income:
Net income (expense) recognized on cash flow hedges	0	0	0	0
Cash flow hedges \| Senior and Subordinated Notes
Interest income:
Net income (expense) recognized on cash flow hedges	0	0	0	0
Cash flow hedges \| Non-Interest Income, Other
Interest income:
Net income (expense) recognized on cash flow hedges	0	0	0	0
Cash flow hedges \| Interest rate contracts: \| Investment Securities
Interest income:
Realized gains (losses) reclassified from AOCI into net income	0	0	0	0
Cash flow hedges \| Interest rate contracts: \| Loans, Including Loans Held for Sale
Interest income:
Realized gains (losses) reclassified from AOCI into net income	(313)	(297)	(622)	(559)
Cash flow hedges \| Interest rate contracts: \| Other
Interest income:
Realized gains (losses) reclassified from AOCI into net income	0	0	0	0
Cash flow hedges \| Interest rate contracts: \| Interest-bearing Deposits
Interest income:
Realized gains (losses) reclassified from AOCI into net income	0	0	0	0
Cash flow hedges \| Interest rate contracts: \| Securitized Debt Obligations
Interest income:
Realized gains (losses) reclassified from AOCI into net income	0	0	0	0
Cash flow hedges \| Interest rate contracts: \| Senior and Subordinated Notes
Interest income:
Realized gains (losses) reclassified from AOCI into net income	0	0	0	0
Cash flow hedges \| Interest rate contracts: \| Non-Interest Income, Other
Interest income:
Realized gains (losses) reclassified from AOCI into net income	0	0	0	0
Cash flow hedges \| Foreign exchange and other contracts \| Investment Securities
Interest income:
Realized gains (losses) reclassified from AOCI into net income	0	0	0	0
Cash flow hedges \| Foreign exchange and other contracts \| Loans, Including Loans Held for Sale
Interest income:
Realized gains (losses) reclassified from AOCI into net income	0	0	0	0
Cash flow hedges \| Foreign exchange and other contracts \| Other
Interest income:
Realized gains (losses) reclassified from AOCI into net income	3	3	5	6
Cash flow hedges \| Foreign exchange and other contracts \| Interest-bearing Deposits
Interest income:
Realized gains (losses) reclassified from AOCI into net income	0	0	0	0
Cash flow hedges \| Foreign exchange and other contracts \| Securitized Debt Obligations
Interest income:
Realized gains (losses) reclassified from AOCI into net income	0	0	0	0
Cash flow hedges \| Foreign exchange and other contracts \| Senior and Subordinated Notes
Interest income:
Realized gains (losses) reclassified from AOCI into net income	0	0	0	0
Cash flow hedges \| Foreign exchange and other contracts \| Non-Interest Income, Other
Interest income:
Realized gains (losses) reclassified from AOCI into net income	$ 0	$ 0	$ 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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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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