Derivatives - Gains and Losses on Derivatives (Details) - Not Designated as Hedging Instrument, Economic Hedge - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Derivative Instruments, Gain (Loss) [Line Items]
Derivative gains (losses)	$ (1,280)	$ 1,432	$ 243
Derivative gains (losses) | Interest-rate risk management derivatives
Derivative Instruments, Gain (Loss) [Line Items]
Derivative gains (losses)	(914)	1,388	391
Derivative gains (losses) | Swap
Derivative Instruments, Gain (Loss) [Line Items]
Derivative gains (losses)	(419)	514	359
Derivative gains (losses) | Written Option | Written
Derivative Instruments, Gain (Loss) [Line Items]
Derivative gains (losses)	364	(134)	170
Derivative gains (losses) | Purchased Options | Purchased
Derivative Instruments, Gain (Loss) [Line Items]
Derivative gains (losses)	(674)	452	(335)
Derivative gains (losses) | Futures
Derivative Instruments, Gain (Loss) [Line Items]
Derivative gains (losses)	(185)	556	197
Derivative gains (losses) | Mortgage commitments derivatives
Derivative Instruments, Gain (Loss) [Line Items]
Derivative gains (losses)	(603)	103	17
Derivative gains (losses) | CRT Related Derivatives
Derivative Instruments, Gain (Loss) [Line Items]
Derivative gains (losses)	48	75	(176)
Derivative gains (losses) | Other
Derivative Instruments, Gain (Loss) [Line Items]
Derivative gains (losses)	$ 189	$ (134)	$ 11