Derivative Instruments - FV Gains and Losses (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2026	Jun. 30, 2025	Jun. 30, 2026	Jun. 30, 2025
Derivative Instruments, Gain (Loss) [Line Items]
Total derivatives fair value gains (losses), net	$ 55	$ (66)	$ 440	$ (401)
Net contractual interest income (expense) on interest-rate swaps	7,493	7,155	14,691	14,156
Pay-fixed
Derivative Instruments, Gain (Loss) [Line Items]
Total derivatives fair value gains (losses), net	1,138	(331)	1,724	(1,210)
Receive-fixed
Derivative Instruments, Gain (Loss) [Line Items]
Total derivatives fair value gains (losses), net	(1,097)	602	(1,774)	1,617
Basis
Derivative Instruments, Gain (Loss) [Line Items]
Total derivatives fair value gains (losses), net	(3)	(11)	6	1
Foreign currency
Derivative Instruments, Gain (Loss) [Line Items]
Total derivatives fair value gains (losses), net	3	23	(7)	32
Pay-fixed
Derivative Instruments, Gain (Loss) [Line Items]
Total derivatives fair value gains (losses), net	22	(1)	(16)	(15)
Receive-fixed
Derivative Instruments, Gain (Loss) [Line Items]
Total derivatives fair value gains (losses), net	(26)	(9)	(5)	(9)
Futures
Derivative Instruments, Gain (Loss) [Line Items]
Total derivatives fair value gains (losses), net	132	2	231	1
Risk management derivatives
Derivative Instruments, Gain (Loss) [Line Items]
Total derivatives fair value gains (losses), net	169	92	146	16
Net contractual interest income (expense) on interest-rate swaps	0	(183)	(13)	(401)
Mortgage commitment derivatives fair value gains (losses), net
Derivative Instruments, Gain (Loss) [Line Items]
Total derivatives fair value gains (losses), net	(105)	(147)	317	(389)
Credit enhancement derivatives
Derivative Instruments, Gain (Loss) [Line Items]
Total derivatives fair value gains (losses), net	(6)	(11)	(16)	(28)
Other derivatives
Derivative Instruments, Gain (Loss) [Line Items]
Total derivatives fair value gains (losses), net	$ (3)	$ 0	$ (7)	$ 0