Allowance for Credit Losses (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Dec. 31, 2021
Allowance for loan losses
Beginning balance	$ 16,386	$ 28,328
Gross charge-offs	2,012	2,656
Gross recoveries collected	(773)	(865)
Net charge-offs/(recoveries)	1,239	1,791
Provision for loan losses	2,598	(7,038)
Other	5	1
Ending balance	17,750	19,500
Allowance for lending-related commitments
Beginning balance	2,261	2,409
Provision for lending-related commitments	(39)	588
Other	0	1
Ending balance	2,222	2,998
Total allowance for investment securities	47	87	$ 42
Total allowance for credit losses	20,019	22,585
Allowance for loan losses by impairment methodology
Asset-specific	(117)	374
Portfolio-based	17,867	19,126
Total allowance for loan losses	17,750	19,500	16,386
Loans by impairment methodology
Asset-specific	15,918	19,377
Portfolio-based	1,036,472	944,288
Total retained loans	1,052,390	963,665	1,010,206
Allowance for lending-related commitments by impairment methodology
Asset-specific	78	150
Portfolio-based	2,144	2,848
Total allowance for lending-related commitments	2,222	2,998	2,261
Lending-related commitments by impairment methodology
Asset-specific	397	851
Portfolio-based	475,171	495,170
Total lending-related commitments	475,568	496,021
Increase in allowance for credit losses	1,300
Collateral-dependent loans
Allowance for loan losses
Net charge-offs/(recoveries)	(7)	29
Collateral-dependent loans
Loans measured at fair value of collateral less cost to sell	4,542	5,030
Consumer-related
Lending-related commitments by impairment methodology
Increase in allowance for credit losses	311
Consumer, excluding credit card
Allowance for loan losses
Beginning balance	1,765	3,636
Gross charge-offs	384	308
Gross recoveries collected	(311)	(318)
Net charge-offs/(recoveries)	73	(10)
Provision for loan losses	237	(1,746)
Other	0	(2)
Ending balance	1,929	1,898
Allowance for lending-related commitments
Beginning balance	113	187
Provision for lending-related commitments	(2)	(46)
Other	(1)	1
Ending balance	110	142
Total allowance for credit losses	2,039	2,040
Allowance for loan losses by impairment methodology
Asset-specific	(676)	(557)
Portfolio-based	2,605	2,455
Total allowance for loan losses	1,929	1,898	1,765
Loans by impairment methodology
Asset-specific	12,683	15,187
Portfolio-based	289,948	282,544
Total retained loans	302,631	297,731	295,556
Allowance for lending-related commitments by impairment methodology
Asset-specific	0	0
Portfolio-based	110	142
Total allowance for lending-related commitments	110	142	113
Lending-related commitments by impairment methodology
Asset-specific	0	0
Portfolio-based	26,809	36,092
Total lending-related commitments	26,809	36,092
Credit card lending-related commitments not permitted to have an allowance for credit losses	13,700	20,800
Consumer, excluding credit card | Collateral-dependent loans
Allowance for loan losses
Net charge-offs/(recoveries)	(15)	23
Collateral-dependent loans
Loans measured at fair value of collateral less cost to sell	3,935	4,689
Credit card
Allowance for loan losses
Beginning balance	10,250	17,800
Gross charge-offs	1,505	2,213
Gross recoveries collected	(419)	(475)
Net charge-offs/(recoveries)	1,086	1,738
Provision for loan losses	1,236	(3,562)
Other	0	0
Ending balance	10,400	12,500
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	10,400	12,500
Allowance for loan losses by impairment methodology
Asset-specific	227	443
Portfolio-based	10,173	12,057
Total allowance for loan losses	10,400	12,500	10,250
Loans by impairment methodology
Asset-specific	827	1,180
Portfolio-based	164,667	139,899
Total retained loans	165,494	141,079
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	774,000	682,500
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	123	135
Gross recoveries collected	(43)	(72)
Net charge-offs/(recoveries)	80	63
Provision for loan losses	1,125	(1,730)
Other	5	3
Ending balance	5,421	5,102
Allowance for lending-related commitments
Beginning balance	2,148	2,222
Provision for lending-related commitments	(37)	634
Other	1	0
Ending balance	2,112	2,856
Total allowance for credit losses	7,533	7,958
Allowance for loan losses by impairment methodology
Asset-specific	332	488
Portfolio-based	5,089	4,614
Total allowance for loan losses	5,421	5,102	4,371
Loans by impairment methodology
Asset-specific	2,408	3,010
Portfolio-based	581,857	521,845
Total retained loans	584,265	524,855	560,354
Allowance for lending-related commitments by impairment methodology
Asset-specific	78	150
Portfolio-based	2,034	2,706
Total allowance for lending-related commitments	2,112	2,856	$ 2,148
Lending-related commitments by impairment methodology
Asset-specific	397	851
Portfolio-based	448,362	459,078
Total lending-related commitments	448,759	459,929
Credit card lending-related commitments not permitted to have an allowance for credit losses	38,700	42,700
Increase in allowance for credit losses	1,000
Wholesale | Collateral-dependent loans
Allowance for loan losses
Net charge-offs/(recoveries)	8	6
Collateral-dependent loans
Loans measured at fair value of collateral less cost to sell	$ 607	$ 341