Reserves for Losses (Details 1) (USD $) In Millions, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Cardmember Receivables And Related Reserves Evaluated Separately and Collectively For Impairment [Abstract]
Cardmember receivables evaluated separately for impairment	$ 119	$ 174
Reserves on cardmember receivables evaluated separately for impairment	80	118
Cardmember receivables evaluated collectively for impairment	42,200	40,716
Reserves on cardmember receivables evaluated collectively for impairment	$ 329	$ 320