Allowance for Credit Losses (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Jan. 01, 2020
Allowance for loan losses
Beginning balance	$ 28,328	$ 13,123	$ 13,445
Gross charge-offs/Write-offs of PCI loans	4,564	6,836	6,810
Gross recoveries collected	(1,699)	(1,577)	(1,181)
Net charge-offs	2,865	5,259	5,629
Provision for loan losses	(9,071)	16,291	5,449
Other	(6)	1	9
Ending balance	16,386	28,328	13,123
Allowance for lending-related commitments
Beginning balance	2,409	1,191	1,055
Provision for lending-related commitments	(149)	1,121	136
Other	1	(1)	0
Ending balance	2,261	2,409	1,191
Total allowance for investment securities	42	78
Total allowance for credit losses	18,689	30,815	14,314
Allowance for loan losses by impairment methodology
Asset-specific	(89)	1,308	847
Portfolio-based	16,475	27,020	11,289
PCI			987
Total allowance for loan losses	16,386	28,328	13,123
Loans by impairment methodology
Asset-specific	17,161	21,629	8,536
Portfolio-based	993,045	938,877	916,702
PCI			20,363
Total retained loans	1,010,206	960,506	945,601
Collateral-dependent loans
Net charge-offs	2,865	5,259	5,629
Allowance for lending-related commitments by impairment methodology
Asset-specific	167	114	102
Portfolio-based	2,094	2,295	1,089
Total allowance for lending-related commitments	2,261	2,409	1,191
Off-Balance Sheet Lending-Related Financial Instruments, Guarantees and Other Commitments [Abstract]
Asset-specific	764	577	474
Portfolio-based	483,159	461,776	423,384
Total lending-related commitments	483,923	462,353	423,858
PCI loans
Allowance for loan losses
Gross charge-offs/Write-offs of PCI loans			151
Collateral-dependent loans
Allowance for loan losses
Net charge-offs	71	209	82
Collateral-dependent loans
Net charge-offs	71	209	82
Loans measured at fair value of collateral less cost to sell	5,089	5,144	2,140
Cumulative effect of change in accounting principles
Allowance for loan losses
Beginning balance		4,172
Ending balance			4,172
Allowance for lending-related commitments
Beginning balance		98
Ending balance			98
Total allowance for investment securities				$ 10
Allowance for loan losses by impairment methodology
Total allowance for loan losses			4,172
Allowance for lending-related commitments by impairment methodology
Total allowance for lending-related commitments			98
Consumer
Off-Balance Sheet Lending-Related Financial Instruments, Guarantees and Other Commitments [Abstract]
Decrease in allowance for credit losses	9,500
Consumer, excluding credit card
Allowance for loan losses
Beginning balance	3,636	2,538	3,434
Gross charge-offs/Write-offs of PCI loans	630	805	902
Gross recoveries collected	(619)	(631)	(536)
Net charge-offs	11	174	366
Provision for loan losses	(1,858)	974	(378)
Other	(2)	1	(1)
Ending balance	1,765	3,636	2,538
Allowance for lending-related commitments
Beginning balance	187	12	12
Provision for lending-related commitments	(75)	42	0
Other	1	0	0
Ending balance	113	187	12
Total allowance for credit losses	1,878	3,823	2,550
Allowance for loan losses by impairment methodology
Asset-specific	(665)	(7)	75
Portfolio-based	2,430	3,643	1,476
PCI			987
Total allowance for loan losses	1,765	3,636	2,538
Loans by impairment methodology
Asset-specific	13,919	16,648	5,961
Portfolio-based	281,637	285,479	268,675
PCI			20,363
Total retained loans	295,556	302,127	294,999
Collateral-dependent loans
Net charge-offs	11	174	366
Allowance for lending-related commitments by impairment methodology
Asset-specific	0	0	0
Portfolio-based	113	187	12
Total allowance for lending-related commitments	113	187	12
Off-Balance Sheet Lending-Related Financial Instruments, Guarantees and Other Commitments [Abstract]
Asset-specific	0	0	0
Portfolio-based	29,588	37,783	30,417
Total lending-related commitments	29,588	37,783	30,417
Credit card lending-related commitments not permitted to have an allowance for credit losses	15,700	19,500	9,800
Consumer, excluding credit card | PCI loans
Allowance for loan losses
Gross charge-offs/Write-offs of PCI loans			151
Consumer, excluding credit card | Collateral-dependent loans
Allowance for loan losses
Net charge-offs	33	133	46
Collateral-dependent loans
Net charge-offs	33	133	46
Loans measured at fair value of collateral less cost to sell	4,472	4,956	2,053
Consumer, excluding credit card | Cumulative effect of change in accounting principles
Allowance for loan losses
Beginning balance		297
Ending balance			297
Allowance for lending-related commitments
Beginning balance		133
Ending balance			133
Allowance for loan losses by impairment methodology
Total allowance for loan losses			297
Allowance for lending-related commitments by impairment methodology
Total allowance for lending-related commitments			133
Credit card
Allowance for loan losses
Beginning balance	17,800	5,683	5,184
Gross charge-offs/Write-offs of PCI loans	3,651	5,077	5,436
Gross recoveries collected	(939)	(791)	(588)
Net charge-offs	2,712	4,286	4,848
Provision for loan losses	(4,838)	10,886	5,348
Other	0	0	(1)
Ending balance	10,250	17,800	5,683
Allowance for lending-related commitments
Beginning balance	0	0	0
Provision for lending-related commitments	0	0	0
Other	0	0	0
Ending balance	0	0	0
Total allowance for credit losses	10,250	17,800	5,683
Allowance for loan losses by impairment methodology
Asset-specific	313	633	477
Portfolio-based	9,937	17,167	5,206
PCI			0
Total allowance for loan losses	10,250	17,800	5,683
Loans by impairment methodology
Asset-specific	987	1,375	1,452
Portfolio-based	153,309	142,057	167,472
PCI			0
Total retained loans	154,296	143,432	168,924
Collateral-dependent loans
Net charge-offs	2,712	4,286	4,848
Allowance for lending-related commitments by impairment methodology
Asset-specific	0	0	0
Portfolio-based	0	0	0
Total allowance for lending-related commitments	0	0	0
Off-Balance Sheet Lending-Related Financial Instruments, Guarantees and Other Commitments [Abstract]
Asset-specific	0	0	0
Portfolio-based	0	0	0
Total lending-related commitments	0	0	0
Credit card lending-related commitments not permitted to have an allowance for credit losses	730,500	658,500	650,700
Credit card | PCI loans
Allowance for loan losses
Gross charge-offs/Write-offs of PCI loans			0
Credit card | Collateral-dependent loans
Allowance for loan losses
Net charge-offs	0	0	0
Collateral-dependent loans
Net charge-offs	0	0	0
Loans measured at fair value of collateral less cost to sell	0	0	0
Credit card | Cumulative effect of change in accounting principles
Allowance for loan losses
Beginning balance		5,517
Ending balance			5,517
Allowance for lending-related commitments
Beginning balance		0
Ending balance			0
Allowance for loan losses by impairment methodology
Total allowance for loan losses			5,517
Allowance for lending-related commitments by impairment methodology
Total allowance for lending-related commitments			0
Wholesale
Allowance for loan losses
Beginning balance	6,892	4,902	4,827
Gross charge-offs/Write-offs of PCI loans	283	954	472
Gross recoveries collected	(141)	(155)	(57)
Net charge-offs	142	799	415
Provision for loan losses	(2,375)	4,431	479
Other	(4)	0	11
Ending balance	4,371	6,892	4,902
Allowance for lending-related commitments
Beginning balance	2,222	1,179	1,043
Provision for lending-related commitments	(74)	1,079	136
Other	0	(1)	0
Ending balance	2,148	2,222	1,179
Total allowance for credit losses	6,519	9,114	6,081
Allowance for loan losses by impairment methodology
Asset-specific	263	682	295
Portfolio-based	4,108	6,210	4,607
PCI			0
Total allowance for loan losses	4,371	6,892	4,902
Loans by impairment methodology
Asset-specific	2,255	3,606	1,123
Portfolio-based	558,099	511,341	480,555
PCI			0
Total retained loans	560,354	514,947	481,678
Collateral-dependent loans
Net charge-offs	142	799	415
Allowance for lending-related commitments by impairment methodology
Asset-specific	167	114	102
Portfolio-based	1,981	2,108	1,077
Total allowance for lending-related commitments	2,148	2,222	1,179
Off-Balance Sheet Lending-Related Financial Instruments, Guarantees and Other Commitments [Abstract]
Asset-specific	764	577	474
Portfolio-based	453,571	423,993	392,967
Total lending-related commitments	454,335	424,570	393,441
Credit card lending-related commitments not permitted to have an allowance for credit losses	32,100	25,300	24,100
Decrease in allowance for credit losses	2,600
Wholesale | PCI loans
Allowance for loan losses
Gross charge-offs/Write-offs of PCI loans			0
Wholesale | Collateral-dependent loans
Allowance for loan losses
Net charge-offs	38	76	36
Collateral-dependent loans
Net charge-offs	38	76	36
Loans measured at fair value of collateral less cost to sell	$ 617	188	87
Wholesale | Cumulative effect of change in accounting principles
Allowance for loan losses
Beginning balance		(1,642)
Ending balance			(1,642)
Allowance for lending-related commitments
Beginning balance		$ (35)
Ending balance			(35)
Allowance for loan losses by impairment methodology
Total allowance for loan losses			(1,642)
Allowance for lending-related commitments by impairment methodology
Total allowance for lending-related commitments			$ (35)