Derivative Financial Instruments - Net Gains (Losses) Relating to Derivative Instruments Designated as Cash Flow Hedges (Details) - Cash Flow Hedging - Interest Income (Expense) Net - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Derivative Instruments, Gain (Loss) [Line Items]
Amount of pre-tax net gains (losses) recognized in OCI	$ (25)	$ 530	$ 373	$ (29)
Amount of pre-tax net losses reclassified from OCI into net income	$ (43)	$ (91)	$ (149)	$ (270)