Reserves for Losses (Details 2) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Changes in the Card Member loans reserve for losses
Balance, January 1	$ 1,201	$ 1,261	$ 1,471
Card Member loans provisions	1,190	1,138	1,115
Card Member loans net write-offs - principal	(967)	(1,023)	(1,141)
Card Member loans net write-offs - interest and fees	(162)	(164)	(150)
Reserves transferred to Held for Sale portfolio	(224)
Card Member loans reserves for losses - other	(10)	(11)	(34)
Balance, December 31	$ 1,028	$ 1,201	$ 1,261