Allowance for Credit Losses and Reserve for Unfunded Lending Commitments - Allowance for Credit Losses and Reserve for Unfunded Lending Commitments Activity (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Allowance for Credit Losses [Roll Forward]
Financing Receivable, Allowance for Credit Loss, Beginning Balance	$ 13,240
Provision for credit losses	2,795	$ 677
Balance at the end of the period	14,318
Financing Receivable Allowance For Credit Loss Translation Adjustments And Purchase Credit Deteriorated Loans	32
Allowance for credit losses
Allowance for Credit Losses [Roll Forward]
Financing Receivable, Allowance for Credit Loss, Beginning Balance	13,240	11,430
Financing Receivable, Allowance for Credit Loss, Writeoff	(2,243)	(1,321)
Recoveries	546	554
Financing Receivable, Allowance for Credit Loss, Writeoff, after Recovery	(1,697)	(767)
Provision for credit losses	2,802	648
Allowance build (release) for credit losses	1,105	(119)
Other changes	36	(3)
Balance at the end of the period	14,318	11,308
Reserve for unfunded lending commitments
Allowance for Credit Losses [Roll Forward]
Financing Receivable, Allowance for Credit Loss, Beginning Balance	218	165
Provision for credit losses	(7)	35
Balance at the end of the period	211	200
Combined allowance and reserve
Allowance for Credit Losses [Roll Forward]
Balance at the end of the period	14,529	11,508
Credit Card | Allowance for credit losses
Allowance for Credit Losses [Roll Forward]
Financing Receivable, Allowance for Credit Loss, Beginning Balance	9,545	8,345
Financing Receivable, Allowance for Credit Loss, Writeoff	(1,688)	(955)
Recoveries	319	348
Financing Receivable, Allowance for Credit Loss, Writeoff, after Recovery	(1,369)	(607)
Provision for credit losses	2,261	545
Allowance build (release) for credit losses	892	(62)
Other changes	36	(3)
Balance at the end of the period	10,410	8,280
Credit Card | Reserve for unfunded lending commitments
Allowance for Credit Losses [Roll Forward]
Financing Receivable, Allowance for Credit Loss, Beginning Balance	0	0
Provision for credit losses	0	0
Balance at the end of the period	0	0
Credit Card | Combined allowance and reserve
Allowance for Credit Losses [Roll Forward]
Balance at the end of the period	10,410	8,280
Consumer Banking | Allowance for credit losses
Allowance for Credit Losses [Roll Forward]
Financing Receivable, Allowance for Credit Loss, Beginning Balance	2,237	1,918
Financing Receivable, Allowance for Credit Loss, Writeoff	(531)	(349)
Recoveries	224	203
Financing Receivable, Allowance for Credit Loss, Writeoff, after Recovery	(307)	(146)
Provision for credit losses	275	130
Allowance build (release) for credit losses	(32)	(16)
Other changes	0	0
Balance at the end of the period	2,205	1,902
Consumer Banking | Reserve for unfunded lending commitments
Allowance for Credit Losses [Roll Forward]
Financing Receivable, Allowance for Credit Loss, Beginning Balance	0	0
Provision for credit losses	0	0
Balance at the end of the period	0	0
Consumer Banking | Combined allowance and reserve
Allowance for Credit Losses [Roll Forward]
Balance at the end of the period	2,205	1,902
Commercial Banking | Allowance for credit losses
Allowance for Credit Losses [Roll Forward]
Financing Receivable, Allowance for Credit Loss, Beginning Balance	1,458	1,167
Financing Receivable, Allowance for Credit Loss, Writeoff	(24)	(17)
Recoveries	3	3
Financing Receivable, Allowance for Credit Loss, Writeoff, after Recovery	(21)	(14)
Provision for credit losses	266	(27)
Allowance build (release) for credit losses	245	(41)
Other changes	0	0
Balance at the end of the period	1,703	1,126
Commercial Banking | Reserve for unfunded lending commitments
Allowance for Credit Losses [Roll Forward]
Financing Receivable, Allowance for Credit Loss, Beginning Balance	218	165
Provision for credit losses	(7)	35
Balance at the end of the period	211	200
Commercial Banking | Combined allowance and reserve
Allowance for Credit Losses [Roll Forward]
Balance at the end of the period	$ 1,914	$ 1,326