Reserves For Losses (Details 3) (USD $) In Millions, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Cardmember Loans And Related Reserves Evaluated Separately And Collectively For Impairment [Abstract]
Cardmember loans evaluated separately for impairment	$ 474	$ 633
Reserves on cardmember loans evaluated separately for impairment	119	153
Cardmember loans evaluated collectively for impairment	62,600	64,596
Reserves on cardmember loans evaluated collectively for impairment	$ 1,223	$ 1,318