Reserves for Losses (Details 1) (USD $) In Millions, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011
Cardmember Receivables And Related Reserves Evaluated Separately and Collectively For Impairment [Abstract]
Cardmember receivables evaluated separately for impairment	$ 145	$ 174
Reserves on cardmember receivables evaluated separately for impairment	110	118
Cardmember receivables evaluated collectively for impairment	41,362	40,716
Reserves on cardmember receivables evaluated collectively for impairment	$ 314	$ 320