Allowance for Credit Losses - Summary (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Dec. 31, 2022
Allowance for loan losses
Beginning balance	$ 19,726	$ 16,386
Gross charge-offs	1,451	976
Gross recoveries collected	(314)	(394)
Net charge-offs/(recoveries)	1,137	582
Provision for loan losses	2,047	1,368
Other	4	20
Ending balance	20,053	17,192
Allowance for lending-related commitments
Beginning balance	2,382	2,261
Provision for lending-related commitments	(13)	96
Other	1	1
Ending balance	2,370	2,358
Total allowance for investment securities	90	41	$ 96
Total allowance for credit losses	22,513	19,591
Allowance for loan losses by impairment methodology
Asset-specific	(593)	103
Portfolio-based	20,646	17,089
Total allowance for loan losses	20,053	17,192	19,726
Loans by impairment methodology
Asset-specific	5,749	16,910
Portfolio-based	1,079,101	1,001,487
Total retained loans	1,084,850	1,018,397	1,089,598
Allowance for lending-related commitments by impairment methodology
Asset-specific	45	139
Portfolio-based	2,325	2,219
Total allowance for lending-related commitments	2,370	2,358	2,382
Lending-related commitments by impairment methodology
Asset-specific	401	767
Portfolio-based	488,169	495,417
Total lending-related commitments	488,570	496,184
Cumulative effect of change in accounting principles
Allowance for loan losses
Beginning balance	(587)
Allowance for loan losses by impairment methodology
Total allowance for loan losses			(587)
CIB
Lending-related commitments by impairment methodology
Allowance for credit losses associated with accounts receivable	20
Corporate
Lending-related commitments by impairment methodology
Allowance for credit losses associated with other assets	241
Collateral-dependent loans
Allowance for loan losses
Net charge-offs/(recoveries)	22	2
Collateral-dependent loans
Loans measured at fair value of collateral less cost to sell	4,125	4,809
Consumer, excluding credit card
Allowance for loan losses
Beginning balance	2,040	1,765
Gross charge-offs	235	204
Gross recoveries collected	(103)	(158)
Net charge-offs/(recoveries)	132	46
Provision for loan losses	247	175
Other	0	0
Ending balance	1,666	1,894
Allowance for lending-related commitments
Beginning balance	76	113
Provision for lending-related commitments	1	(2)
Other	0	0
Ending balance	77	111
Total allowance for credit losses	1,743	2,005
Allowance for loan losses by impairment methodology
Asset-specific	(1,030)	(644)
Portfolio-based	2,696	2,538
Total allowance for loan losses	1,666	1,894	2,040
Loans by impairment methodology
Asset-specific	3,560	13,186
Portfolio-based	296,887	282,975
Total retained loans	300,447	296,161	300,753
Allowance for lending-related commitments by impairment methodology
Asset-specific	0	0
Portfolio-based	77	111
Total allowance for lending-related commitments	77	111	76
Lending-related commitments by impairment methodology
Asset-specific	0	0
Portfolio-based	21,569	31,847
Total lending-related commitments	21,569	31,847
Credit card lending-related commitments not permitted to have an allowance for credit losses	16,000	15,300
Consumer, excluding credit card | Cumulative effect of change in accounting principles
Allowance for loan losses
Beginning balance	(489)
Allowance for loan losses by impairment methodology
Total allowance for loan losses			(489)
Consumer, excluding credit card | Collateral-dependent loans
Allowance for loan losses
Net charge-offs/(recoveries)	4	(5)
Collateral-dependent loans
Loans measured at fair value of collateral less cost to sell	3,539	4,144
Credit card
Allowance for loan losses
Beginning balance	11,200	10,250
Gross charge-offs	1,111	720
Gross recoveries collected	(189)	(214)
Net charge-offs/(recoveries)	922	506
Provision for loan losses	1,222	506
Other	0	0
Ending balance	11,400	10,250
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	11,400	10,250
Allowance for loan losses by impairment methodology
Asset-specific	0	262
Portfolio-based	11,400	9,988
Total allowance for loan losses	11,400	10,250	11,200
Loans by impairment methodology
Asset-specific	0	901
Portfolio-based	180,079	151,382
Total retained loans	180,079	152,283
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	861,200	757,300
Credit card | Cumulative effect of change in accounting principles
Allowance for loan losses
Beginning balance	(100)
Allowance for loan losses by impairment methodology
Total allowance for loan losses			(100)
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	6,486	4,371
Gross charge-offs	105	52
Gross recoveries collected	(22)	(22)
Net charge-offs/(recoveries)	83	30
Provision for loan losses	578	687
Other	4	20
Ending balance	6,987	5,048
Allowance for lending-related commitments
Beginning balance	2,306	2,148
Provision for lending-related commitments	(14)	98
Other	1	1
Ending balance	2,293	2,247
Total allowance for credit losses	9,280	7,295
Allowance for loan losses by impairment methodology
Asset-specific	437	485
Portfolio-based	6,550	4,563
Total allowance for loan losses	6,987	5,048	6,486
Loans by impairment methodology
Asset-specific	2,189	2,823
Portfolio-based	602,135	567,130
Total retained loans	604,324	569,953	603,670
Allowance for lending-related commitments by impairment methodology
Asset-specific	45	139
Portfolio-based	2,248	2,108
Total allowance for lending-related commitments	2,293	2,247	2,306
Lending-related commitments by impairment methodology
Asset-specific	401	767
Portfolio-based	466,600	463,570
Total lending-related commitments	467,001	464,337
Credit card lending-related commitments not permitted to have an allowance for credit losses	17,500	32,900
Wholesale | Cumulative effect of change in accounting principles
Allowance for loan losses
Beginning balance	2
Allowance for loan losses by impairment methodology
Total allowance for loan losses			$ 2
Wholesale | Collateral-dependent loans
Allowance for loan losses
Net charge-offs/(recoveries)	18	7
Collateral-dependent loans
Loans measured at fair value of collateral less cost to sell	$ 586	$ 665