Reserves (Details 1) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014
Changes in the Card Member loans reserve for losses
Balance, January 1	$ 3	$ 4
Provisions	3	4
Net write-offs	(2)	(3)
Balance, June 30	$ 4	$ 5