Loans and Card Member Receivables (Details 1) - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Card Member Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivables, gross	$ 77,026	$ 73,373
Card Member Receivables
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivables, gross	48,758	43,701
GCSG | Card Member Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivables, gross	61,625	60,084
GCSG | Card Member Receivables
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivables, gross	19,499	18,685
GCSG | Current | Card Member Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivables, gross	61,178	59,442
GCSG | Current | Card Member Receivables
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivables, gross	19,400	18,570
GCSG | 30 to 59 Days Past Due | Card Member Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivables, gross	144	177
GCSG | 30 to 59 Days Past Due | Card Member Receivables
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivables, gross	38	33
GCSG | 60 to 89 Days Past Due | Card Member Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivables, gross	100	148
GCSG | 60 to 89 Days Past Due | Card Member Receivables
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivables, gross	22	26
GCSG | 90+ Days Past Due | Card Member Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivables, gross	203	317
GCSG | 90+ Days Past Due | Card Member Receivables
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivables, gross	39	56
GCS | Card Member Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivables, gross	15,401	13,289
GCS | Card Member Loans | Global Small Business Services
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivables, gross	15,349	13,226
GCS | Card Member Loans | Global Corporate Payments
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivables, gross	52	63
GCS | Card Member Receivables
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivables, gross	29,259	25,016
GCS | Card Member Receivables | Global Small Business Services
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivables, gross	16,781	14,119
GCS | Card Member Receivables | Global Corporate Payments
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivables, gross	12,478	10,897
GCS | Current | Card Member Loans | Global Small Business Services
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivables, gross	15,272	13,132
GCS | Current | Card Member Receivables | Global Small Business Services
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivables, gross	16,684	14,023
GCS | 30 to 59 Days Past Due | Card Member Loans | Global Small Business Services
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivables, gross	29	27
GCS | 30 to 59 Days Past Due | Card Member Receivables | Global Small Business Services
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivables, gross	42	37
GCS | 60 to 89 Days Past Due | Card Member Loans | Global Small Business Services
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivables, gross	19	20
GCS | 60 to 89 Days Past Due | Card Member Receivables | Global Small Business Services
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivables, gross	24	21
GCS | 90+ Days Past Due | Card Member Loans | Global Small Business Services
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivables, gross	29	47
GCS | 90+ Days Past Due | Card Member Loans | Global Corporate Payments
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivables, gross	0	0
GCS | 90+ Days Past Due | Card Member Receivables | Global Small Business Services
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivables, gross	31	38
GCS | 90+ Days Past Due | Card Member Receivables | Global Corporate Payments
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivables, gross	$ 35	$ 60