Derivative Instruments - Summary of Gains (Losses) Recognized in Earnings for Other Economic Hedges and Customer-Related Positions (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]	Noninterest Income	Noninterest Income	Noninterest Income	Noninterest Income
Customer-Related Positions [Member] | Interest Rate Contracts [Member] | Options [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recognized in earnings	$ 7	$ 6	$ 7	$ 10
Customer-Related Positions [Member] | Interest Rate Contracts [Member] | Futures [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recognized in earnings	0	7	(1)	31
Customer-Related Positions [Member] | Swaps [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recognized in earnings	103	26	198	73
Customer-Related Positions [Member] | Foreign Exchange Rate Contracts [Member] | Options [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recognized in earnings	0	0	0	1
Customer-Related Positions [Member] | Foreign Exchange Rate Contracts [Member] | Forwards, Spots and Swaps [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recognized in earnings	19	40	118	75
Customer-Related Positions [Member] | Commodity Contract [Member] | Swap [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recognized in earnings	3	0	5	0
Customer-Related Positions [Member] | Credit Contracts [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recognized in earnings	0	(1)	(1)	21
Asset and Liability Management Positions [Member] | Other Economic Hedges [Member] | Interest Rate Contracts [Member] | Futures and Forwards [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recognized in earnings	18	142	56	439
Asset and Liability Management Positions [Member] | Other Economic Hedges [Member] | Interest Rate Contracts [Member] | Options [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recognized in earnings	74	(28)	89	(69)
Asset and Liability Management Positions [Member] | Other Economic Hedges [Member] | Swaps [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recognized in earnings	(241)	(118)	(221)	(569)
Asset and Liability Management Positions [Member] | Other Economic Hedges [Member] | Foreign Exchange Forward Contracts [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recognized in earnings	8	12	(5)	13
Asset and Liability Management Positions [Member] | Other Economic Hedges [Member] | Equity Contracts [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recognized in earnings	(1)	(1)	(4)	(4)
Asset and Liability Management Positions [Member] | Other Economic Hedges [Member] | Other Derivatives [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recognized in earnings	1	(154)	0	(154)
Asset and Liability Management Positions [Member] | Customer-Related Positions [Member] | Credit Contracts [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recognized in earnings	$ 3	$ 0	$ 3	$ 0