Card Member Receivables and Card Member Loans (Details) - USD ($) $ in Millions	Mar. 31, 2021	Dec. 31, 2020	Mar. 31, 2020	Dec. 31, 2019
Card Member Receivables
Financing Receivable Segment [Abstract]
Financing receivables, gross	$ 11,545	$ 12,157
Less: Reserves for credit losses	30	70	$ 69	$ 15
Financing receivables, net	11,515	12,087
Deferred discount (expense) revenue on card member receivable	21	19
Card Member Loans
Financing Receivable Segment [Abstract]
Less: Reserves for credit losses	24	20	$ 18	$ 17
Financing receivables, net	435	480
Global Consumer Services Group | Card Member Receivables
Financing Receivable Segment [Abstract]
Financing receivables, gross	1,889	2,157
Global Consumer Services Group | Card Member Loans
Financing Receivable Segment [Abstract]
Financing receivables, gross	459	500
Less: Reserves for credit losses	24	20
Financing receivables, net	435	480
Global Commercial Services | Card Member Receivables
Financing Receivable Segment [Abstract]
Financing receivables, gross	$ 9,656	$ 10,000