Discontinued Operations - Summary of Assets and Liabilities of Disposal Group Held for Sale (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Assets of discontinued operations	$ 13	$ 63
Liabilities of discontinued operations	102	71
Card and Retail Services [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Assets of discontinued operations	8	1
Liabilities of discontinued operations	$ 102	$ 71