Loans and Card Member Receivables (Details) - USD ($) $ in Millions	Mar. 31, 2022	Dec. 31, 2021	Mar. 31, 2021	Dec. 31, 2020
Card Member Loans
Loans segment information
Financing receivables, gross	$ 88,832	$ 88,562
Less: Reserves for credit losses	2,981	3,305	$ 4,467	$ 5,344
Financing receivables, net	85,851	85,257
Other Loans
Loans segment information
Less: Reserves for credit losses	48	52
Financing receivables, net	3,264	2,859
Card Member Receivables
Loans segment information
Financing receivables, gross	53,164	53,645
Less: Reserves for credit losses	76	64	$ 202	$ 267
Financing receivables, net	53,088	53,581
Variable Interest Entity, Primary Beneficiary | Card Member Loans
Loans segment information
Financing receivables, gross	26,017	26,587
Variable Interest Entity, Primary Beneficiary | Card Member Receivables
Loans segment information
Financing receivables, gross	5,640	5,175
GCSG | Card Member Loans
Loans segment information
Financing receivables, gross	69,480	70,467
GCSG | Card Member Receivables
Loans segment information
Financing receivables, gross	20,644	22,392
GCSG | Variable Interest Entity, Primary Beneficiary | Card Member Loans
Loans segment information
Financing receivables, gross	26,000	26,600
GCS | Card Member Loans
Loans segment information
Financing receivables, gross	19,352	18,095
GCS | Card Member Receivables
Loans segment information
Financing receivables, gross	32,520	31,253
GCS | Variable Interest Entity, Primary Beneficiary | Card Member Receivables
Loans segment information
Financing receivables, gross	$ 5,600	$ 5,200