Discontinued Operations - Operating Results of Discontinued Operations (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2015		Mar. 31, 2014
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Income (loss) from discontinued operations before income tax	$ 0		$ (11)
Commercial Business [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net interest income and other revenues	7		2
Income (loss) from discontinued operations before income tax	4		1
Card and Retail Services [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net interest income and other revenues	0		0
Income (loss) from discontinued operations before income tax	$ (4)	[1]	$ (12)	[1]

[1] For the three months ended March 31, 2015 and 2014, the amounts include expenses related to activities to complete the separation of the credit card operational infrastructure between us and Capital One. We expect costs associated with the separation of the credit card operational infrastructure to continue in 2015.