Reserves for Losses (Details 2) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Changes in the Card Member receivables reserve for losses
Balance, January 1	$ 462	$ 465	$ 386
Provision For Doubtful Accounts	696	737	792
Card Member receivables net write-offs	(674)	(713)	(683)
Other	(17)	(27)	(30)
Balance, December 31	$ 467	$ 462	$ 465