Loans and Card Member Receivables (Details 2) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Card Member Loans [Member]
Financing receivable recorded investment aging
Financing receivables, gross	$ 73,373	$ 87,381
Card Member Receivables [Member]
Financing receivable recorded investment aging
Financing receivables, gross	43,701	57,413
Global Consumer Services Group [Member] | Card Member Loans [Member]
Financing receivable recorded investment aging
Financing receivables, current	59,442	72,101
Financing receivables, gross	60,084	73,266
Global Consumer Services Group [Member] | Card Member Receivables [Member]
Financing receivable recorded investment aging
Financing receivables, current	18,570	22,560
Financing receivables, gross	18,685	22,844
Global Consumer Services Group [Member] | Financing Receivables, 30 to 59 Days Past Due [Member] | Card Member Loans [Member]
Financing receivable recorded investment aging
Financing receivables, past due	177	322
Global Consumer Services Group [Member] | Financing Receivables, 30 to 59 Days Past Due [Member] | Card Member Receivables [Member]
Financing receivable recorded investment aging
Financing receivables, past due	33	86
Global Consumer Services Group [Member] | Financing Receivables, 60 to 89 Days Past Due [Member] | Card Member Loans [Member]
Financing receivable recorded investment aging
Financing receivables, past due	148	253
Global Consumer Services Group [Member] | Financing Receivables, 60 to 89 Days Past Due [Member] | Card Member Receivables [Member]
Financing receivable recorded investment aging
Financing receivables, past due	26	58
Global Consumer Services Group [Member] | 90+ days past due [Member] | Card Member Loans [Member]
Financing receivable recorded investment aging
Financing receivables, past due	317	590
Global Consumer Services Group [Member] | 90+ days past due [Member] | Card Member Receivables [Member]
Financing receivable recorded investment aging
Financing receivables, past due	56	140
Global Small Business Services [Member] | Card Member Loans [Member]
Financing receivable recorded investment aging
Financing receivables, current	13,132	13,898
Financing receivables, gross	13,226	14,079
Global Small Business Services [Member] | Card Member Receivables [Member]
Financing receivable recorded investment aging
Financing receivables, current	14,023	17,113
Financing receivables, gross	14,119	17,404
Global Small Business Services [Member] | Financing Receivables, 30 to 59 Days Past Due [Member] | Card Member Loans [Member]
Financing receivable recorded investment aging
Financing receivables, past due	27	56
Global Small Business Services [Member] | Financing Receivables, 30 to 59 Days Past Due [Member] | Card Member Receivables [Member]
Financing receivable recorded investment aging
Financing receivables, past due	37	99
Global Small Business Services [Member] | Financing Receivables, 60 to 89 Days Past Due [Member] | Card Member Loans [Member]
Financing receivable recorded investment aging
Financing receivables, past due	20	40
Global Small Business Services [Member] | Financing Receivables, 60 to 89 Days Past Due [Member] | Card Member Receivables [Member]
Financing receivable recorded investment aging
Financing receivables, past due	21	58
Global Small Business Services [Member] | 90+ days past due [Member] | Card Member Loans [Member]
Financing receivable recorded investment aging
Financing receivables, past due	47	85
Global Small Business Services [Member] | 90+ days past due [Member] | Card Member Receivables [Member]
Financing receivable recorded investment aging
Financing receivables, past due	38	134
Global Corporate Payments [Member] | Card Member Loans [Member]
Financing receivable recorded investment aging
Financing receivables, gross	63	36
Global Corporate Payments [Member] | Card Member Receivables [Member]
Financing receivable recorded investment aging
Financing receivables, gross	10,897	17,165
Global Corporate Payments [Member] | 90+ days past due [Member] | Card Member Loans [Member]
Financing receivable recorded investment aging
Financing receivables, past due	0	0
Global Corporate Payments [Member] | 90+ days past due [Member] | Card Member Receivables [Member]
Financing receivable recorded investment aging
Financing receivables, past due	$ 60	$ 136