Derivative Financial Instruments and Hedging Activities - Schedule of Fair Value (Details) - USD ($) $ in Millions	Mar. 31, 2025	Dec. 31, 2024
Derivatives, Fair Value [Line Items]
Notional	$ 172,490	$ 169,727
Fair Value of Assets	870	981
Fair Value of Liabilities	1,715	2,427
Fair value of assets (liabilities) available for offset	693	693
Other Liabilities
Derivatives, Fair Value [Line Items]
Collateral held for netting against asset positions	104	190
Other Assets
Derivatives, Fair Value [Line Items]
Collateral available for netting against liability positions	898	1,200
Interest rate swaps | Fair value hedges | Level 2 | Derivatives designated as hedges
Derivatives, Fair Value [Line Items]
Notional	44,495	36,145
Fair Value of Assets	127	32
Fair Value of Liabilities	589	621
Interest rate swaps | Cash flow hedges | Level 2 | Derivatives designated as hedges
Derivatives, Fair Value [Line Items]
Notional	2,006	1,873
Fair Value of Assets	28	35
Fair Value of Liabilities	17	4
Foreign currency swaps | Cash flow hedges | Level 2 | Derivatives designated as hedges
Derivatives, Fair Value [Line Items]
Notional	8,420	8,363
Fair Value of Assets	137	80
Fair Value of Liabilities	231	508
Interest rate contracts | Level 2 | Derivatives not designated as hedges
Derivatives, Fair Value [Line Items]
Notional	117,569	123,346
Fair Value of Assets	578	833
Fair Value of Liabilities	$ 879	$ 1,294