Details of Certain Consolidated Statements of Income Lines (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Component of Other Income, Nonoperating [Line Items]
Total other commissions and fees	$ 573	$ 583
Foreign currency conversion revenue [Member]
Component of Other Income, Nonoperating [Line Items]
Total other commissions and fees	210	207
Delinquency fees [Member]
Component of Other Income, Nonoperating [Line Items]
Total other commissions and fees	164	162
Service fees [Member]
Component of Other Income, Nonoperating [Line Items]
Total other commissions and fees	82	93
Other commissions and fees [Member]
Component of Other Income, Nonoperating [Line Items]
Total other commissions and fees	$ 117	$ 121