Derivative Instruments and Hedging Activities - Effects of Fair Value and Cash Flow Hedge Accounting (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Interest income:
Investment Securities	$ 823	$ 733	$ 2,377	$ 2,120
Loans, Including Loans Held for Sale	15,229	10,547	37,835	30,460
Other	711	580	1,797	1,737
Interest-bearing Deposits	(3,597)	(2,945)	(9,432)	(8,631)
Securitized Debt Obligations	(165)	(234)	(505)	(753)
Senior and Subordinated Notes	(582)	(596)	(1,622)	(1,793)
Non-interest income (expense)	294	244	910	803
Amortization expense (benefit)	23	21	49	62
Non-Interest Income, Other
Interest income:
Realized gain (loss) on foreign exchange contracts reclassified from AOCI	83	(56)	(63)	(1)
Fair value hedges \| Investment Securities
Interest income:
Net income (expense) recognized on fair value hedges	10	23	36	74
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	(22)	(72)	(87)	(277)
Fair value hedges \| Securitized Debt Obligations
Interest income:
Net income (expense) recognized on fair value hedges	(37)	(102)	(123)	(339)
Fair value hedges \| Senior and Subordinated Notes
Interest income:
Net income (expense) recognized on fair value hedges	(121)	(211)	(356)	(649)
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	15	39	69	125
Gains (losses) recognized on derivatives	(18)	(144)	(178)	(137)
Gains (losses) recognized on hedged items	13	128	145	86
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	(22)	(73)	(87)	(277)
Gains (losses) recognized on derivatives	16	247	131	213
Gains (losses) recognized on hedged items	(16)	(246)	(131)	(213)
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	(36)	(102)	(122)	(339)
Gains (losses) recognized on derivatives	19	210	136	261
Gains (losses) recognized on hedged items	(20)	(210)	(137)	(261)
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	(147)	(248)	(441)	(771)
Gains (losses) recognized on derivatives	103	1,010	887	742
Gains (losses) recognized on hedged items	(77)	(973)	(801)	(627)
Excluded component of fair value hedges	0	0	(1)	7
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	(2)	21	70	(18)
Gains (losses) recognized on hedged items	2	(21)	(70)	18
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	(2)	0	(2)	0
Cash flow hedges \| Loans, Including Loans Held for Sale
Interest income:
Net income (expense) recognized on cash flow hedges	(238)	(314)	(716)	(936)
Cash flow hedges \| Other
Interest income:
Net income (expense) recognized on cash flow hedges	4	2	9	7
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	1	1	1
Cash flow hedges \| Interest rate contracts: \| Investment Securities
Interest income:
Realized gains (losses) reclassified from AOCI into net income	(2)	0	(2)	0
Cash flow hedges \| Interest rate contracts: \| Loans, Including Loans Held for Sale
Interest income:
Realized gains (losses) reclassified from AOCI into net income	(238)	(314)	(716)	(936)
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	4	2	9	7
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	$ 1	$ 1	$ 1

Amortization of Basis Adjustment on Discontinued Hedges

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