Discontinued Operations - Operating Results of Discontinued Operations (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Income (loss) from discontinued operations before income tax		$ (54)	$ (27)	$ (249)
Insurance Business [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net interest income and other revenues		0	0	70
Income (loss) from discontinued operations before income tax		0	0	(10)
Commercial Business [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net interest income and other revenues		14	10	22
Income (loss) from discontinued operations before income tax		8	6	14
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	1
Income (loss) from discontinued operations before income tax	[1]	(62)	(33)	(253)
Incremental increase in industry review enhancement expense		$ 41	$ 7	$ 87

[1] For 2014 and 2013, the amounts also include expenses related to activities to complete the separation of the credit card operational infrastructure between us and Capital One