Reserves for Credit Losses (Details 1) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Jan. 01, 2020
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	$ 619
Provisions	597	$ 253
Net write-offs	(258)	(216)
Other	(6)	(2)
Ending balance	459	608
Decrease in Card Member receivable reserves	(619)	(608)
Recoveries	92	91
Accounting Standards Update 2016-13 [Member]
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	126	573
Decrease in Card Member receivable reserves	(126)	(573)	$ 493
Troubled Debt Restructuring [Member]
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Net write-offs	(7)	(4)
Foreign Currency Translation Adjustments [Member]
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Other	$ (5)	$ 3