Allowance for Credit Losses (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021
Allowance for loan losses
Beginning balance	$ 16,386	$ 28,328
Gross charge-offs	976	1,468
Gross recoveries collected	(394)	(411)
Net charge-offs/(recoveries)	582	1,057
Provision for loan losses	1,368	(4,279)
Other	20	9
Ending balance	17,192	23,001
Allowance for lending-related commitments
Beginning balance	2,261	2,409
Provision for lending-related commitments	96	107
Other	1	0
Ending balance	2,358	2,516
Total allowance for investment securities	41	94	$ 42
Total allowance for credit losses	19,591	25,611	18,700
Allowance for loan losses by impairment methodology
Asset-specific	103	703
Portfolio-based	17,089	22,298
Total allowance for loan losses	17,192	23,001	16,386
Loans by impairment methodology
Asset-specific	16,910	20,693
Portfolio-based	1,001,487	927,949
Total retained loans	1,018,397	948,642	1,010,206
Allowance for lending-related commitments by impairment methodology
Asset-specific	139	144
Portfolio-based	2,219	2,372
Total allowance for lending-related commitments	2,358	2,516	2,261
Lending-related commitments by impairment methodology
Asset-specific	767	800
Portfolio-based	495,417	475,298
Total lending-related commitments	496,184	476,098
Collateral-dependent loans
Allowance for loan losses
Net charge-offs/(recoveries)	2	22
Collateral-dependent loans
Loans measured at fair value of collateral less cost to sell	4,809	5,144
Consumer-related
Lending-related commitments by impairment methodology
Increase in allowance for credit losses	127
Consumer, excluding credit card
Allowance for loan losses
Beginning balance	1,765	3,636
Gross charge-offs	204	166
Gross recoveries collected	(158)	(145)
Net charge-offs/(recoveries)	46	21
Provision for loan losses	175	(932)
Other	0	(1)
Ending balance	1,894	2,682
Allowance for lending-related commitments
Beginning balance	113	187
Provision for lending-related commitments	(2)	(52)
Other	0	0
Ending balance	111	135
Total allowance for credit losses	2,005	2,817
Allowance for loan losses by impairment methodology
Asset-specific	(644)	(348)
Portfolio-based	2,538	3,030
Total allowance for loan losses	1,894	2,682	1,765
Loans by impairment methodology
Asset-specific	13,186	16,008
Portfolio-based	282,975	286,384
Total retained loans	296,161	302,392	295,556
Allowance for lending-related commitments by impairment methodology
Asset-specific	0	0
Portfolio-based	111	135
Total allowance for lending-related commitments	111	135	113
Lending-related commitments by impairment methodology
Asset-specific	0	0
Portfolio-based	31,847	34,468
Total lending-related commitments	31,847	34,468
Credit card lending-related commitments not permitted to have an allowance for credit losses	15,300	21,800
Consumer, excluding credit card | Collateral-dependent loans
Allowance for loan losses
Net charge-offs/(recoveries)	(5)	20
Collateral-dependent loans
Loans measured at fair value of collateral less cost to sell	4,144	4,790
Credit card
Allowance for loan losses
Beginning balance	10,250	17,800
Gross charge-offs	720	1,214
Gross recoveries collected	(214)	(231)
Net charge-offs/(recoveries)	506	983
Provision for loan losses	506	(2,517)
Other	0	0
Ending balance	10,250	14,300
Allowance for lending-related commitments
Beginning balance	0	0
Provision for lending-related commitments	0	0
Other	0	0
Ending balance	0	0
Total allowance for credit losses	10,250	14,300
Allowance for loan losses by impairment methodology
Asset-specific	262	522
Portfolio-based	9,988	13,778
Total allowance for loan losses	10,250	14,300	10,250
Loans by impairment methodology
Asset-specific	901	1,291
Portfolio-based	151,382	130,481
Total retained loans	152,283	131,772
Allowance for lending-related commitments by impairment methodology
Asset-specific	0	0
Portfolio-based	0	0
Total allowance for lending-related commitments	0	0	0
Lending-related commitments by impairment methodology
Asset-specific	0	0
Portfolio-based	0	0
Total lending-related commitments	0	0
Credit card lending-related commitments not permitted to have an allowance for credit losses	757,300	674,400
Credit card | Collateral-dependent loans
Allowance for loan losses
Net charge-offs/(recoveries)	0	0
Collateral-dependent loans
Loans measured at fair value of collateral less cost to sell	0	0
Wholesale
Allowance for loan losses
Beginning balance	4,371	6,892
Gross charge-offs	52	88
Gross recoveries collected	(22)	(35)
Net charge-offs/(recoveries)	30	53
Provision for loan losses	687	(830)
Other	20	10
Ending balance	5,048	6,019
Allowance for lending-related commitments
Beginning balance	2,148	2,222
Provision for lending-related commitments	98	159
Other	1	0
Ending balance	2,247	2,381
Total allowance for credit losses	7,295	8,400
Allowance for loan losses by impairment methodology
Asset-specific	485	529
Portfolio-based	4,563	5,490
Total allowance for loan losses	5,048	6,019	4,371
Loans by impairment methodology
Asset-specific	2,823	3,394
Portfolio-based	567,130	511,084
Total retained loans	569,953	514,478	560,354
Allowance for lending-related commitments by impairment methodology
Asset-specific	139	144
Portfolio-based	2,108	2,237
Total allowance for lending-related commitments	2,247	2,381	$ 2,148
Lending-related commitments by impairment methodology
Asset-specific	767	800
Portfolio-based	463,570	440,830
Total lending-related commitments	464,337	441,630
Credit card lending-related commitments not permitted to have an allowance for credit losses	32,900	39,600
Increase in allowance for credit losses	776
Wholesale | Collateral-dependent loans
Allowance for loan losses
Net charge-offs/(recoveries)	7	2
Collateral-dependent loans
Loans measured at fair value of collateral less cost to sell	$ 665	$ 354