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, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Interest income:
Investment Securities	$ 784	$ 700	$ 1,554	$ 1,387
Loans, Including Loans Held for Sale	12,449	9,993	22,606	19,913
Other	595	587	1,086	1,157
Interest-bearing Deposits	(3,120)	(2,874)	(5,835)	(5,686)
Securitized Debt Obligations	(164)	(258)	(340)	(519)
Senior and Subordinated Notes	(535)	(591)	(1,040)	(1,197)
Non-interest income (expense)	361	252	616	559
Amortization expense (benefit)	16	18	26	41
Non-Interest Income, Other
Interest income:
Realized gain (loss) on foreign exchange contracts reclassified from AOCI	(20)	(19)	(146)	55
Fair value hedges \| Investment Securities
Interest income:
Net income (expense) recognized on fair value hedges	12	24	26	51
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	(30)	(98)	(65)	(205)
Fair value hedges \| Securitized Debt Obligations
Interest income:
Net income (expense) recognized on fair value hedges	(36)	(119)	(86)	(237)
Fair value hedges \| Senior and Subordinated Notes
Interest income:
Net income (expense) recognized on fair value hedges	(115)	(210)	(235)	(438)
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	22	41	54	86
Gains (losses) recognized on derivatives	(62)	(14)	(160)	7
Gains (losses) recognized on hedged items	52	(3)	132	(42)
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	(30)	(97)	(65)	(204)
Gains (losses) recognized on derivatives	40	37	115	(34)
Gains (losses) recognized on hedged items	(40)	(38)	(115)	33
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	(37)	(119)	(86)	(237)
Gains (losses) recognized on derivatives	44	70	117	51
Gains (losses) recognized on hedged items	(43)	(70)	(117)	(51)
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	(146)	(256)	(294)	(523)
Gains (losses) recognized on derivatives	309	48	784	(268)
Gains (losses) recognized on hedged items	(277)	(10)	(724)	346
Excluded component of fair value hedges	(1)	8	(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	49	(8)	72	(39)
Gains (losses) recognized on hedged items	(49)	8	(72)	39
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	(1)	0	0	0
Cash flow hedges \| Loans, Including Loans Held for Sale
Interest income:
Net income (expense) recognized on cash flow hedges	(237)	(313)	(478)	(622)
Cash flow hedges \| Other
Interest income:
Net income (expense) recognized on cash flow hedges	3	3	5	5
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	2	0	1	0
Cash flow hedges \| Interest rate contracts: \| Investment Securities
Interest income:
Realized gains (losses) reclassified from AOCI into net income	(1)	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	(237)	(313)	(478)	(622)
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	5
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	$ 2	$ 0	$ 1	$ 0

Amortization of Basis Adjustment on Discontinued Hedges

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