Derivative Financial Instruments and Hedging Activities - Derivative Financial Instruments (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Derivatives, Fair Value [Line Items]
Notional	$ 169,727	$ 163,446
Fair Value of Assets	981	1,809
Fair Value of Liabilities	$ 2,427	$ 2,563
Derivative Asset, Statement of Financial Position [Extensible Enumeration]	Other assets (Note 8)	Other assets (Note 8)
Derivative Liability, Statement of Financial Position [Extensible Enumeration]	Other liabilities	Other liabilities
Fair value of assets (liabilities) available for offset	$ 693	$ 1,200
Other Liabilities
Derivatives, Fair Value [Line Items]
Cash held for netting against asset positions	190	457
Other Assets
Derivatives, Fair Value [Line Items]
Collateral available for netting against liability positions	1,200	1,200
Interest rate swaps | Fair value hedges | Level 2 | Derivatives Designated as Hedges
Derivatives, Fair Value [Line Items]
Notional	36,145	18,379
Fair Value of Assets	32	75
Fair Value of Liabilities	621	238
Interest rate swaps | Cash flow hedges | Level 2 | Derivatives Designated as Hedges
Derivatives, Fair Value [Line Items]
Notional	1,873	2,381
Fair Value of Assets	35	17
Fair Value of Liabilities	4	16
Foreign currency swaps | Cash flow hedges | Level 2 | Derivatives Designated as Hedges
Derivatives, Fair Value [Line Items]
Notional	8,363	8,003
Fair Value of Assets	80	144
Fair Value of Liabilities	508	311
Interest rate contracts | Level 2 | Derivatives not Designated as Hedges
Derivatives, Fair Value [Line Items]
Notional	123,346	134,683
Fair Value of Assets	833	1,573
Fair Value of Liabilities	$ 1,294	$ 1,997