Loans and Card Member Receivables - Impaired Loans and Receivables, Prior to Adoption (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Impaired loans and receivables
Loans over 90 days past due and accruing interest		$ 309	$ 169
Non-accruals		191	96
Account classified as a TDR in program		1,733	1,332
Account classified as a TDR out of program		2,068	1,764
Total impaired loans and receivables		4,301	3,361
Reserve for Credit Losses - TDRs		$ 504	596
Accounts Receivable and Loans Textuals
Threshold period past due for write-off		180 days
Account classified as TDR, past due 90 days and still accruing		$ 48	41
Accounts classified as TDR, non-accrual		17	19
Out of Program TDR accounts that completed modification programs		1,922	1,621
Out of Program TDR accounts not in compliance with modification programs		146	143
Card Member loans
Accounts Receivable and Loans Textuals
Threshold period past due for write-off	180 days
Card Member loans | Consumer
Impaired loans and receivables
Loans over 90 days past due and accruing interest	$ 393	252	149
Non-accruals	344	155	82
Account classified as a TDR in program		781	708
Account classified as a TDR out of program		1,098	997
Total impaired loans and receivables		2,286	1,936
Reserve for Credit Losses - TDRs		335	415
Card Member loans | Small Business
Impaired loans and receivables
Loans over 90 days past due and accruing interest	109	54	19
Non-accruals	95	34	14
Account classified as a TDR in program		267	176
Account classified as a TDR out of program		380	332
Total impaired loans and receivables		735	541
Reserve for Credit Losses - TDRs		108	132
Card Member loans | Corporate
Impaired loans and receivables
Loans over 90 days past due and accruing interest	0	0	0
Non-accruals	$ 0	0	0
Account classified as a TDR in program		0	0
Account classified as a TDR out of program		0	0
Total impaired loans and receivables		0	0
Reserve for Credit Losses - TDRs		0	0
Card Member receivables
Accounts Receivable and Loans Textuals
Threshold period past due for write-off	180 days
Card Member receivables | Consumer
Impaired loans and receivables
Loans over 90 days past due and accruing interest	$ 0	0	0
Non-accruals	0	0	0
Account classified as a TDR in program		257	133
Account classified as a TDR out of program		179	130
Total impaired loans and receivables		436	263
Reserve for Credit Losses - TDRs		20	9
Card Member receivables | Small Business
Impaired loans and receivables
Loans over 90 days past due and accruing interest	0	0	0
Non-accruals	0	0	0
Account classified as a TDR in program		403	247
Account classified as a TDR out of program		402	297
Total impaired loans and receivables		805	544
Reserve for Credit Losses - TDRs		40	39
Card Member receivables | Corporate
Impaired loans and receivables
Loans over 90 days past due and accruing interest	0	0	0
Non-accruals	$ 0	0	0
Account classified as a TDR in program		6	1
Account classified as a TDR out of program		7	6
Total impaired loans and receivables		13	7
Reserve for Credit Losses - TDRs		1	0
Other loans
Impaired loans and receivables
Loans over 90 days past due and accruing interest		3	1
Non-accruals		2	0
Account classified as a TDR in program		19	67
Account classified as a TDR out of program		2	2
Total impaired loans and receivables		26	70
Reserve for Credit Losses - TDRs		$ 0	$ 1