Fair Value Measurements - Changes in Fair Value of Level 3 Assets and Liabilities (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Derivatives liability
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Total liabilities, ending balance	$ (233)	$ (504)
Level 3
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Total assets, beginning balance	145	319
Assets, Total Realized/Unrealized Gains (Losses) Included in Earnings	(116)	(70)
Assets, Total Realized/Unrealized Gains (Losses) Included in Other Comprehensive Income (Loss)	(3)	1
Assets, Purchases	0	0
Assets, Issuances	1	3
Assets, Settlements	8	(50)
Assets, Transfers Into Level 3	28	0
Assets Transfers out of Level 3	43	(1)
Total assets, ending balance	106	202
Assets, Current Period Unrealized Gains (Losses) Still Held Included in Earnings	(93)	(70)
Assets, Current Period Unrealized Gains (Losses) Still Held Included in Other Comprehensive Income	(3)	1
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Total liabilities, beginning balance	(2,388)	(1,094)
Total Realized/Unrealized Gains (Losses) Included in Earnings	115	1
Total Realized/Unrealized Gains (Losses) Included in Other Comprehensive Income	3	0
Purchases	0	0
Issuances	(300)	(123)
Settlements	172	117
Transfers Into Level 3	(255)	(2)
Transfers Out of Level 3	89	16
Total liabilities, ending balance	(2,564)	(1,085)
Current Period Unrealized Gains (Losses) Still Held Included in Earnings	86	12
Current Period Unrealized Gains (Losses) Still Held Included in Other Comprehensive Income	3	0
Level 3 | Interest rate contracts
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Derivatives, net, Beginning Balance	0	34
Derivatives, net, Total Realized/Unrealized Gains (Losses) Included in Earnings	0	(32)
Derivatives, net, Total Realized/Unrealized Gains (Losses) Included in Other Comprehensive Income	0	0
Derivatives, net, Purchases	0	0
Derivatives, net, Issuances	0	0
Derivatives, net, Settlements	0	0
Derivatives, net, Transfers into Level 3	(1)	0
Derivatives, net, Transfers out of Level 3	0	0
Derivatives, net, Ending Balance	(1)	2
Derivatives, net, Current Period Unrealized Gains (Losses) Still Held Included in Earnings	(1)	(17)
Derivatives, net, Current Period Unrealized Gains (Losses) Still Held Included in Other Comprehensive Income (Loss)	0	0
Level 3 | Foreign exchange contracts
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Derivatives, net, Beginning Balance	(2)	9
Derivatives, net, Total Realized/Unrealized Gains (Losses) Included in Earnings	1	(11)
Derivatives, net, Total Realized/Unrealized Gains (Losses) Included in Other Comprehensive Income	0	0
Derivatives, net, Purchases	0	0
Derivatives, net, Issuances	0	0
Derivatives, net, Settlements	0	0
Derivatives, net, Transfers into Level 3	0	0
Derivatives, net, Transfers out of Level 3	0	0
Derivatives, net, Ending Balance	(1)	(2)
Derivatives, net, Current Period Unrealized Gains (Losses) Still Held Included in Earnings	1	(12)
Derivatives, net, Current Period Unrealized Gains (Losses) Still Held Included in Other Comprehensive Income (Loss)	0	0
Level 3 | Equity contracts
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Derivatives, net, Beginning Balance	46	119
Derivatives, net, Total Realized/Unrealized Gains (Losses) Included in Earnings	(120)	(22)
Derivatives, net, Total Realized/Unrealized Gains (Losses) Included in Other Comprehensive Income	0	0
Derivatives, net, Purchases	0	0
Derivatives, net, Issuances	0	0
Derivatives, net, Settlements	1	(54)
Derivatives, net, Transfers into Level 3	29	0
Derivatives, net, Transfers out of Level 3	43	(1)
Derivatives, net, Ending Balance	(1)	42
Derivatives, net, Current Period Unrealized Gains (Losses) Still Held Included in Earnings	(95)	(32)
Derivatives, net, Current Period Unrealized Gains (Losses) Still Held Included in Other Comprehensive Income (Loss)	0	0
Level 3 | Credit contracts
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Derivatives, net, Beginning Balance	(2)	63
Derivatives, net, Total Realized/Unrealized Gains (Losses) Included in Earnings	0	(17)
Derivatives, net, Total Realized/Unrealized Gains (Losses) Included in Other Comprehensive Income	0	0
Derivatives, net, Purchases	0	0
Derivatives, net, Issuances	0	0
Derivatives, net, Settlements	0	(1)
Derivatives, net, Transfers into Level 3	0	0
Derivatives, net, Transfers out of Level 3	0	0
Derivatives, net, Ending Balance	(2)	45
Derivatives, net, Current Period Unrealized Gains (Losses) Still Held Included in Earnings	0	(19)
Derivatives, net, Current Period Unrealized Gains (Losses) Still Held Included in Other Comprehensive Income (Loss)	0	0
Level 3 | Other Contracts
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Derivatives, net, Beginning Balance	(33)	(59)
Derivatives, net, Total Realized/Unrealized Gains (Losses) Included in Earnings	(1)	2
Derivatives, net, Total Realized/Unrealized Gains (Losses) Included in Other Comprehensive Income	0	0
Derivatives, net, Purchases	0	0
Derivatives, net, Issuances	0	0
Derivatives, net, Settlements	10	7
Derivatives, net, Transfers into Level 3	0	0
Derivatives, net, Transfers out of Level 3	0	0
Derivatives, net, Ending Balance	(24)	(50)
Derivatives, net, Current Period Unrealized Gains (Losses) Still Held Included in Earnings	0	0
Derivatives, net, Current Period Unrealized Gains (Losses) Still Held Included in Other Comprehensive Income (Loss)	0	0
Mortgage servicing rights | Level 3
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Total assets, beginning balance	16	7
Assets, Total Realized/Unrealized Gains (Losses) Included in Earnings	4	1
Assets, Total Realized/Unrealized Gains (Losses) Included in Other Comprehensive Income (Loss)	0	0
Assets, Purchases	0	0
Assets, Issuances	1	3
Assets, Settlements	0	0
Assets, Transfers Into Level 3	0	0
Assets Transfers out of Level 3	0	0
Total assets, ending balance	21	11
Assets, Current Period Unrealized Gains (Losses) Still Held Included in Earnings	2	1
Assets, Current Period Unrealized Gains (Losses) Still Held Included in Other Comprehensive Income	0	0
Derivative assets
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Total assets, ending balance	204	541
Asset-backed securities collateralized by residential mortgages | Trading assets, excluding derivatives: | Level 3
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Total assets, beginning balance		15
Assets, Total Realized/Unrealized Gains (Losses) Included in Earnings		9
Assets, Total Realized/Unrealized Gains (Losses) Included in Other Comprehensive Income (Loss)		0
Assets, Purchases		0
Assets, Issuances		0
Assets, Settlements		0
Assets, Transfers Into Level 3		0
Assets Transfers out of Level 3		0
Total assets, ending balance		24
Assets, Current Period Unrealized Gains (Losses) Still Held Included in Earnings		9
Assets, Current Period Unrealized Gains (Losses) Still Held Included in Other Comprehensive Income		0
Other | Securities available-for-sale ("AFS") | Level 3
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Total assets, beginning balance	120	131
Assets, Total Realized/Unrealized Gains (Losses) Included in Earnings	0	0
Assets, Total Realized/Unrealized Gains (Losses) Included in Other Comprehensive Income (Loss)	(3)	1
Assets, Purchases	0	0
Assets, Issuances	0	0
Assets, Settlements	(3)	(2)
Assets, Transfers Into Level 3	0	0
Assets Transfers out of Level 3	0	0
Total assets, ending balance	114	130
Assets, Current Period Unrealized Gains (Losses) Still Held Included in Earnings	0	0
Assets, Current Period Unrealized Gains (Losses) Still Held Included in Other Comprehensive Income	(3)	1
Domestic Deposits | Level 3
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Total liabilities, beginning balance	(535)	(646)
Total Realized/Unrealized Gains (Losses) Included in Earnings	21	4
Total Realized/Unrealized Gains (Losses) Included in Other Comprehensive Income	(2)	0
Purchases	0	0
Issuances	0	0
Settlements	70	28
Transfers Into Level 3	(49)	0
Transfers Out of Level 3	3	15
Total liabilities, ending balance	(492)	(599)
Current Period Unrealized Gains (Losses) Still Held Included in Earnings	19	8
Current Period Unrealized Gains (Losses) Still Held Included in Other Comprehensive Income	(2)	0
Fixed rate long-term debt | Level 3
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Total liabilities, beginning balance	(1,853)	(448)
Total Realized/Unrealized Gains (Losses) Included in Earnings	94	(3)
Total Realized/Unrealized Gains (Losses) Included in Other Comprehensive Income	5	0
Purchases	0	0
Issuances	(300)	(123)
Settlements	102	89
Transfers Into Level 3	(206)	(2)
Transfers Out of Level 3	86	1
Total liabilities, ending balance	(2,072)	(486)
Current Period Unrealized Gains (Losses) Still Held Included in Earnings	67	4
Current Period Unrealized Gains (Losses) Still Held Included in Other Comprehensive Income	$ 5	$ 0