Derivative Instruments - Gains (Losses) Recognized in Earnings for Other Economic Hedges and Customer-Related Positions (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Customer-Related Positions | Interest rate contracts | Purchased and written options
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recognized in earnings	$ 2	$ (21)	$ 14	$ (68)
Customer-Related Positions | Interest rate contracts | Futures
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recognized in earnings	1	0	2	0
Customer-Related Positions | Swaps
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recognized in earnings	47	89	82	220
Customer-Related Positions | Credit contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recognized in earnings	(8)	1	(6)	0
Customer-Related Positions | Foreign exchange rate contracts | Purchased and written options
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recognized in earnings	0	0	1	0
Customer-Related Positions | Foreign exchange rate contracts | Forwards, spots and swaps
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recognized in earnings	66	32	114	56
Customer-Related Positions | Commodity contracts | Purchased and written options
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recognized in earnings	15	2	14	4
Customer-Related Positions | Commodity contracts | Futures
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recognized in earnings	45	6	4	6
Customer-Related Positions | Commodity contracts | Swaps
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recognized in earnings	(43)	(1)	4	1
Asset and Liability Management Positions | Other economic hedges | Interest rate contracts | Futures and forwards
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recognized in earnings	1	(2)	25	(14)
Asset and Liability Management Positions | Other economic hedges | Interest rate contracts | Purchased and written options
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recognized in earnings	38	9	68	48
Asset and Liability Management Positions | Other economic hedges | Swaps
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recognized in earnings	13	9	69	(77)
Asset and Liability Management Positions | Other economic hedges | Foreign exchange forward contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recognized in earnings	(19)	4	(17)	8
Asset and Liability Management Positions | Other economic hedges | Equity contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recognized in earnings	27	(2)	8	(2)
Asset and Liability Management Positions | Other economic hedges | Credit contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recognized in earnings	(12)	0	5	(2)
Asset and Liability Management Positions | Other economic hedges | Other
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recognized in earnings	$ (82)	$ 6	$ (82)	$ (69)