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, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Customer-Related Positions | Interest rate contracts | Purchased and written options
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recognized in earnings	$ (21)	$ (1)	$ (68)	$ 0
Customer-Related Positions | Interest rate contracts | Futures
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recognized in earnings	0	0	0	(1)
Customer-Related Positions | Swaps
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recognized in earnings	89	58	220	95
Customer-Related Positions | Credit contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recognized in earnings	1	(1)	0	(1)
Customer-Related Positions | Foreign exchange rate contracts | Forwards, spots and swaps
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recognized in earnings	32	44	56	99
Customer-Related Positions | Commodity contracts | Purchased and written options
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recognized in earnings	2	0	4	0
Customer-Related Positions | Commodity contracts | Futures
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recognized in earnings	6	0	6	0
Customer-Related Positions | Commodity contracts | Swaps
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recognized in earnings	(1)	2	1	2
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	(2)	31	(14)	38
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	9	17	48	15
Asset and Liability Management Positions | Other economic hedges | Swaps
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recognized in earnings	9	(38)	(77)	20
Asset and Liability Management Positions | Other economic hedges | Foreign exchange forward contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recognized in earnings	4	(8)	8	(13)
Asset and Liability Management Positions | Other economic hedges | Equity contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recognized in earnings	(2)	0	(2)	(3)
Asset and Liability Management Positions | Other economic hedges | Credit contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recognized in earnings	0	0	(2)	0
Asset and Liability Management Positions | Other economic hedges | Other
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recognized in earnings	$ 6	$ 1	$ (69)	$ (1)