Reserves for Credit Losses (Details 2) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Provisions	$ (14)	$ 103
Card Member Receivables
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance	70	15
Provisions	(22)	100
Net write-offs	(18)	(50)
Other adjustments	0	4
Ending Balance	30	69
Recoveries	$ 21	24
Card Member Receivables | Global Consumer Services Group
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Removal of financing receivables		$ 7,200