Guarantees (Details) (USD $)	Mar. 31, 2014	Dec. 31, 2013
Type of Guarantee
Maximum potential amount of undiscounted future payments	$ 43,000,000,000	$ 45,000,000,000
Amount of related liability	120,000,000	161,000,000
Card and Travel Operations [Member]
Type of Guarantee
Maximum potential amount of undiscounted future payments	42,000,000,000	44,000,000,000
Amount of related liability	46,000,000	88,000,000
Other Guarantees [Member]
Type of Guarantee
Maximum potential amount of undiscounted future payments	1,000,000,000	1,000,000,000
Amount of related liability	$ 74,000,000	$ 73,000,000