Card Member Receivables and Card Member Loans (Details) - USD ($) $ in Millions		3 Months Ended
	Feb. 01, 2020	Mar. 31, 2020	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Financing Receivable Segment [Abstract]
Reduction of Card member receivables (U.S. consumer Card Member receivables)		$ 7,200
Card Member Receivables [Member]
Financing Receivable Segment [Abstract]
Financing receivables			$ 12,157	$ 25,557
Financing receivables, reserves for credit losses			70	162	$ 167	$ 145
Financing receivables, net			12,087	25,395
Reduction of Card member receivables (U.S. consumer Card Member receivables)	$ 7,200
Net of deferred discount revenues			19	75
Global Consumer Services Group [Member] | Card Member Receivables [Member]
Financing Receivable Segment [Abstract]
Financing receivables			2,157	9,847
Reduction of Card member receivables (U.S. consumer Card Member receivables)	$ 7,200
Global Commercial Services [Member] | Card Member Receivables [Member]
Financing Receivable Segment [Abstract]
Financing receivables			$ 10,000	$ 15,710