Fair Value Measurements - Changes in Fair Value of Level 3 Assets and Liabilities (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Fair Value, Recurring
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Gross Balance, Assets	$ 74,511	$ 97,982
Gross Balance, Liabilities	28,125	49,380
Fair Value, Recurring | Derivatives
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Gross Balance, Liabilities	15,285	31,461
Interest rate contracts | Fair Value, Recurring | Derivatives
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Gross Balance, Liabilities	1,899	6,625
Foreign exchange contracts | Fair Value, Recurring | Derivatives
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Gross Balance, Liabilities	11,126	18,603
Equity contracts | Fair Value, Recurring | Derivatives
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Gross Balance, Liabilities	1,361	4,291
Credit contracts | Fair Value, Recurring | Derivatives
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Gross Balance, Liabilities	82	297
Other Contracts | Fair Value, Recurring | Derivatives
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Gross Balance, Liabilities	38	67
Derivative
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Total assets, beginning balance	692
Total assets, ending balance	219	692
Derivatives
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Total liabilities, beginning balance	(526)
Total liabilities, ending balance	(210)	(526)
Level 3
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Total assets, beginning balance	319	707
Assets, Total Realized/Unrealized Gains (Losses) Included in Earnings	(317)	132
Assets, Total Realized/Unrealized Gains (Losses) Included in Other Comprehensive Income (Loss)	(3)	(9)
Assets, Purchases	0	0
Assets, Issuances	9	5
Assets, Settlements	104	(521)
Assets, Transfers Into Level 3	(27)	3
Assets Transfers out of Level 3	60	2
Total assets, ending balance	145	319
Assets, Current Period Unrealized Gains (Losses) Still Held Included in Earnings	8	158
Assets, Current Period Unrealized Gains (Losses) Still Held Included in Other Comprehensive Income	(3)	(9)
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Total liabilities, beginning balance	(1,094)	(1,128)
Total Realized/Unrealized Gains (Losses) Included in Earnings	(51)	(27)
Total Realized/Unrealized Gains (Losses) Included in Other Comprehensive Income	2	(2)
Purchases	0	0
Issuances	(1,732)	(305)
Settlements	592	284
Transfers Into Level 3	(251)	(1)
Transfers Out of Level 3	146	85
Total liabilities, ending balance	(2,388)	(1,094)
Current Period Unrealized Gains (Losses) Still Held Included in Earnings	(29)	(50)
Current Period Unrealized Gains (Losses) Still Held Included in Other Comprehensive Income	2	(2)
Level 3 | Fair Value, Recurring
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Gross Balance, Assets	355	845
Gross Balance, Liabilities	2,598	1,620
Level 3 | Fair Value, Recurring | Derivatives
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Gross Balance, Liabilities	210	526
Level 3 | Interest rate contracts
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Derivatives, net, Beginning Balance	34	10
Derivatives, net, Total Realized/Unrealized Gains (Losses) Included in Earnings	(34)	23
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	1
Derivatives, net, Transfers out of Level 3	0	0
Derivatives, net, Ending Balance	0	34
Derivatives, net, Current Period Unrealized Gains (Losses) Still Held Included in Earnings	(4)	23
Derivatives, net, Current Period Unrealized Gains (Losses) Still Held Included in Other Comprehensive Income (Loss)	0	0
Level 3 | Interest rate contracts | Fair Value, Recurring | Derivatives
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Gross Balance, Liabilities	1	1
Level 3 | Foreign exchange contracts
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Derivatives, net, Beginning Balance	9	(1)
Derivatives, net, Total Realized/Unrealized Gains (Losses) Included in Earnings	(11)	(1)
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	11
Derivatives, net, Transfers out of Level 3	0	0
Derivatives, net, Ending Balance	(2)	9
Derivatives, net, Current Period Unrealized Gains (Losses) Still Held Included in Earnings	0	(1)
Derivatives, net, Current Period Unrealized Gains (Losses) Still Held Included in Other Comprehensive Income (Loss)	0	0
Level 3 | Foreign exchange contracts | Fair Value, Recurring | Derivatives
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Gross Balance, Liabilities	2	6
Level 3 | Equity contracts
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Derivatives, net, Beginning Balance	119	72
Derivatives, net, Total Realized/Unrealized Gains (Losses) Included in Earnings	(214)	129
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	84	(47)
Derivatives, net, Transfers into Level 3	(27)	(37)
Derivatives, net, Transfers out of Level 3	84	2
Derivatives, net, Ending Balance	46	119
Derivatives, net, Current Period Unrealized Gains (Losses) Still Held Included in Earnings	14	147
Derivatives, net, Current Period Unrealized Gains (Losses) Still Held Included in Other Comprehensive Income (Loss)	0	0
Level 3 | Equity contracts | Fair Value, Recurring | Derivatives
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Gross Balance, Liabilities	167	446
Level 3 | Credit contracts
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Derivatives, net, Beginning Balance	63	59
Derivatives, net, Total Realized/Unrealized Gains (Losses) Included in Earnings	(65)	7
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	(3)
Derivatives, net, Transfers into Level 3	0	0
Derivatives, net, Transfers out of Level 3	0	0
Derivatives, net, Ending Balance	(2)	63
Derivatives, net, Current Period Unrealized Gains (Losses) Still Held Included in Earnings	(2)	(7)
Derivatives, net, Current Period Unrealized Gains (Losses) Still Held Included in Other Comprehensive Income (Loss)	0	0
Level 3 | Credit contracts | Fair Value, Recurring | Derivatives
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Gross Balance, Liabilities	2	6
Level 3 | Other Contracts
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Derivatives, net, Beginning Balance	(59)	(75)
Derivatives, net, Total Realized/Unrealized Gains (Losses) Included in Earnings	(2)	(9)
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	28	25
Derivatives, net, Transfers into Level 3	0	0
Derivatives, net, Transfers out of Level 3	0	0
Derivatives, net, Ending Balance	(33)	(59)
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
Level 3 | Other Contracts | Fair Value, Recurring | Derivatives
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Gross Balance, Liabilities	38	67
Mortgage servicing rights | Level 3
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Total assets, beginning balance	7	4
Assets, Total Realized/Unrealized Gains (Losses) Included in Earnings	0	(2)
Assets, Total Realized/Unrealized Gains (Losses) Included in Other Comprehensive Income (Loss)	0	0
Assets, Purchases	0	0
Assets, Issuances	9	5
Assets, Settlements	0	0
Assets, Transfers Into Level 3	0	0
Assets Transfers out of Level 3	0	0
Total assets, ending balance	16	7
Assets, Current Period Unrealized Gains (Losses) Still Held Included in Earnings	0	(2)
Assets, Current Period Unrealized Gains (Losses) Still Held Included in Other Comprehensive Income	0	0
Derivative | Fair Value, Recurring
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Gross Balance, Assets	16,229	32,468
Derivative | Interest rate contracts | Fair Value, Recurring
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Gross Balance, Assets	1,848	6,687
Derivative | Foreign exchange contracts | Fair Value, Recurring
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Gross Balance, Assets	11,350	18,467
Derivative | Equity contracts | Fair Value, Recurring
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Gross Balance, Assets	2,058	5,616
Derivative | Credit contracts | Fair Value, Recurring
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Gross Balance, Assets	28	367
Derivative | Other Contracts | Fair Value, Recurring
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Gross Balance, Assets	5	8
Derivative | Level 3 | Fair Value, Recurring
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Gross Balance, Assets	219	692
Derivative | Level 3 | Interest rate contracts | Fair Value, Recurring
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Gross Balance, Assets	1	35
Derivative | Level 3 | Foreign exchange contracts | Fair Value, Recurring
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Gross Balance, Assets	0	15
Derivative | Level 3 | Equity contracts | Fair Value, Recurring
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Gross Balance, Assets	213	565
Derivative | Level 3 | Credit contracts | Fair Value, Recurring
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Gross Balance, Assets	0	69
Derivative | Level 3 | Other Contracts | Fair Value, Recurring
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Gross Balance, Assets	5	8
Asset-backed securities collateralized by residential mortgages | Trading assets, excluding derivatives: | Fair Value, Recurring
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Gross Balance, Assets		15
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	17
Assets, Total Realized/Unrealized Gains (Losses) Included in Earnings	9	(2)
Assets, Total Realized/Unrealized Gains (Losses) Included in Other Comprehensive Income (Loss)	0	0
Assets, Purchases	0	0
Assets, Issuances	0	0
Assets, Settlements	0	0
Assets, Transfers Into Level 3	0	0
Assets Transfers out of Level 3	(24)	0
Total assets, ending balance	0	15
Assets, Current Period Unrealized Gains (Losses) Still Held Included in Earnings	0	(2)
Assets, Current Period Unrealized Gains (Losses) Still Held Included in Other Comprehensive Income	0	0
Asset-backed securities collateralized by residential mortgages | Trading assets, excluding derivatives: | Level 3 | Fair Value, Recurring
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Gross Balance, Assets		15
Corporate and other domestic debt securities | Trading assets, excluding derivatives: | Level 3
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Total assets, beginning balance	0	510
Assets, Total Realized/Unrealized Gains (Losses) Included in Earnings		(13)
Assets, Total Realized/Unrealized Gains (Losses) Included in Other Comprehensive Income (Loss)		0
Assets, Purchases		0
Assets, Issuances		0
Assets, Settlements		(497)
Assets, Transfers Into Level 3		0
Assets Transfers out of Level 3		0
Total assets, ending balance		0
Assets, Current Period Unrealized Gains (Losses) Still Held Included in Earnings		0
Assets, Current Period Unrealized Gains (Losses) Still Held Included in Other Comprehensive Income		0
Other | Securities available-for-sale ("AFS") | Fair Value, Recurring
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Gross Balance, Assets	101	104
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	131	111
Assets, Total Realized/Unrealized Gains (Losses) Included in Earnings	0	0
Assets, Total Realized/Unrealized Gains (Losses) Included in Other Comprehensive Income (Loss)	(3)	(9)
Assets, Purchases	0	0
Assets, Issuances	0	0
Assets, Settlements	(8)	1
Assets, Transfers Into Level 3	0	28
Assets Transfers out of Level 3	0	0
Total assets, ending balance	120	131
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)	(9)
Other | Securities available-for-sale ("AFS") | Level 3 | Fair Value, Recurring
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Gross Balance, Assets	101	104
Domestic Deposits | Level 3
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Total liabilities, beginning balance	(646)	(774)
Total Realized/Unrealized Gains (Losses) Included in Earnings	(16)	(15)
Total Realized/Unrealized Gains (Losses) Included in Other Comprehensive Income	2	(2)
Purchases	0	0
Issuances	0	(43)
Settlements	184	125
Transfers Into Level 3	(151)	0
Transfers Out of Level 3	92	63
Total liabilities, ending balance	(535)	(646)
Current Period Unrealized Gains (Losses) Still Held Included in Earnings	(16)	(20)
Current Period Unrealized Gains (Losses) Still Held Included in Other Comprehensive Income	2	(2)
Fixed rate long-term debt | Level 3
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Total liabilities, beginning balance	(448)	(354)
Total Realized/Unrealized Gains (Losses) Included in Earnings	(35)	(12)
Total Realized/Unrealized Gains (Losses) Included in Other Comprehensive Income	0	0
Purchases	0	0
Issuances	(1,732)	(262)
Settlements	408	159
Transfers Into Level 3	(100)	(1)
Transfers Out of Level 3	54	22
Total liabilities, ending balance	(1,853)	(448)
Current Period Unrealized Gains (Losses) Still Held Included in Earnings	(13)	(30)
Current Period Unrealized Gains (Losses) Still Held Included in Other Comprehensive Income	$ 0	$ 0