Loans and Card Member Receivables (Details 1) - USD ($) $ in Millions	Mar. 31, 2021	Dec. 31, 2020
Card Member Loans
Financing receivable recorded investment aging
Total	$ 70,100	$ 73,373
Card Member Receivables
Financing receivable recorded investment aging
Total	42,002	43,701
GCSG | Card Member Loans
Financing receivable recorded investment aging
Current	55,728	59,442
Total	56,265	60,084
GCSG | Card Member Receivables
Financing receivable recorded investment aging
Current	17,129	18,570
Total	17,228	18,685
GCSG | 30 to 59 Days Past Due | Card Member Loans
Financing receivable recorded investment aging
Period past due	139	177
GCSG | 30 to 59 Days Past Due | Card Member Receivables
Financing receivable recorded investment aging
Period past due	29	33
GCSG | 60 to 89 Days Past Due | Card Member Loans
Financing receivable recorded investment aging
Period past due	106	148
GCSG | 60 to 89 Days Past Due | Card Member Receivables
Financing receivable recorded investment aging
Period past due	20	26
GCSG | 90+ Days Past Due | Card Member Loans
Financing receivable recorded investment aging
Period past due	292	317
GCSG | 90+ Days Past Due | Card Member Receivables
Financing receivable recorded investment aging
Period past due	50	56
GCS | Card Member Loans
Financing receivable recorded investment aging
Total	13,835	13,289
GCS | Card Member Loans | Global Small Business Services
Financing receivable recorded investment aging
Current	13,682	13,132
Total	13,762	13,226
GCS | Card Member Loans | Global Corporate Payments
Financing receivable recorded investment aging
Total	73	63
GCS | Card Member Receivables
Financing receivable recorded investment aging
Total	24,774	25,016
GCS | Card Member Receivables | Global Small Business Services
Financing receivable recorded investment aging
Current	14,191	14,023
Total	14,277	14,119
GCS | Card Member Receivables | Global Corporate Payments
Financing receivable recorded investment aging
Total	10,497	10,897
GCS | 30 to 59 Days Past Due | Card Member Loans | Global Small Business Services
Financing receivable recorded investment aging
Period past due	24	27
GCS | 30 to 59 Days Past Due | Card Member Receivables | Global Small Business Services
Financing receivable recorded investment aging
Period past due	33	37
GCS | 60 to 89 Days Past Due | Card Member Loans | Global Small Business Services
Financing receivable recorded investment aging
Period past due	18	20
GCS | 60 to 89 Days Past Due | Card Member Receivables | Global Small Business Services
Financing receivable recorded investment aging
Period past due	21	21
GCS | 90+ Days Past Due | Card Member Loans | Global Small Business Services
Financing receivable recorded investment aging
Period past due	38	47
GCS | 90+ Days Past Due | Card Member Loans | Global Corporate Payments
Financing receivable recorded investment aging
Period past due	0	0
GCS | 90+ Days Past Due | Card Member Receivables | Global Small Business Services
Financing receivable recorded investment aging
Period past due	32	38
GCS | 90+ Days Past Due | Card Member Receivables | Global Corporate Payments
Financing receivable recorded investment aging
Period past due	$ 47	$ 60