Discontinued Operations - Additional Information (Details) - USD ($)	Jun. 30, 2015	Dec. 31, 2014
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Assets of discontinued operations	$ 21,000,000	$ 63,000,000
Liabilities of discontinued operations	60,000,000	71,000,000
Commercial Business [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Assets of discontinued operations	21,000,000	62,000,000
Liabilities of discontinued operations	0	0
Card and Retail Services [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Assets of discontinued operations	0	1,000,000
Liabilities of discontinued operations	60,000,000	$ 71,000,000
Minimum [Member] | Card and Retail Services [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Portion of reasonable possible loss not accrued for	0
Maximum [Member] | Card and Retail Services [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Portion of reasonable possible loss not accrued for	$ 500,000,000