Loans and Card Member Receivables (Details 1) - USD ($) $ in Millions	Jun. 30, 2021	Dec. 31, 2020
Card Member Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivables, gross	$ 75,610	$ 73,373
Card Member Receivables
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivables, gross	47,585	43,701
GCSG | Card Member Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivables, gross	60,561	60,084
GCSG | Card Member Receivables
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivables, gross	19,932	18,685
GCSG | Current | Card Member Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivables, gross	60,138	59,442
GCSG | Current | Card Member Receivables
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivables, gross	19,844	18,570
GCSG | 30 to 59 Days Past Due | Card Member Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivables, gross	119	177
GCSG | 30 to 59 Days Past Due | Card Member Receivables
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivables, gross	34	33
GCSG | 60 to 89 Days Past Due | Card Member Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivables, gross	86	148
GCSG | 60 to 89 Days Past Due | Card Member Receivables
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivables, gross	16	26
GCSG | 90+ Days Past Due | Card Member Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivables, gross	218	317
GCSG | 90+ Days Past Due | Card Member Receivables
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivables, gross	38	56
GCS | Card Member Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivables, gross	15,049	13,289
GCS | Card Member Loans | Global Small Business Services
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivables, gross	14,994	13,226
GCS | Card Member Loans | Global Corporate Payments
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivables, gross	55	63
GCS | Card Member Receivables
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivables, gross	27,653	25,016
GCS | Card Member Receivables | Global Small Business Services
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivables, gross	15,929	14,119
GCS | Card Member Receivables | Global Corporate Payments
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivables, gross	11,724	10,897
GCS | Current | Card Member Loans | Global Small Business Services
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivables, gross	14,927	13,132
GCS | Current | Card Member Receivables | Global Small Business Services
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivables, gross	15,853	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	22	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	32	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	14	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	14	21
GCS | 90+ Days Past Due | Card Member Loans | Global Small Business Services
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivables, gross	31	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	30	38
GCS | 90+ Days Past Due | Card Member Receivables | Global Corporate Payments
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivables, gross	$ 32	$ 60