Derivative Instruments - Gains (Losses) Recognized in Earnings for Other Economic Hedges and Customer-Related Positions (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Customer-Related Positions | Interest rate contracts | Purchased and written options
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recognized in earnings	$ 109	$ 7	$ 41	$ 7
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	(55)	103	165	198
Customer-Related Positions | Credit contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recognized in earnings	(3)	0	(3)	(1)
Customer-Related Positions | Foreign exchange rate contracts | Forwards, spots and swaps
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recognized in earnings	70	19	126	118
Customer-Related Positions | Commodity contracts | Purchased and written options
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recognized in earnings	1	0	5	0
Customer-Related Positions | Commodity contracts | Futures
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recognized in earnings	4	0	10	0
Customer-Related Positions | Commodity contracts | Swaps
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recognized in earnings	(2)	3	(1)	5
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	18	(12)	56
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	64	74	112	89
Asset and Liability Management Positions | Other economic hedges | Swaps
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recognized in earnings	107	(241)	30	(221)
Asset and Liability Management Positions | Other economic hedges | Foreign exchange forward contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recognized in earnings	(6)	8	2	(5)
Asset and Liability Management Positions | Other economic hedges | Equity contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recognized in earnings	(2)	(1)	(4)	(4)
Asset and Liability Management Positions | Other economic hedges | Credit contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recognized in earnings	(5)	3	(7)	3
Asset and Liability Management Positions | Other economic hedges | Other
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recognized in earnings	$ (1)	$ 1	$ (70)	$ 0