Other Assets (Schedule of Other Assets) (Details) - USD ($) $ in Millions	Jun. 30, 2017	Dec. 31, 2016	Aug. 01, 2016	Jun. 01, 2016
Goodwill [Line Items]
Goodwill	$ 240	$ 240
Property, Plant and Equipment, Gross	985	901
Accumulated depreciation	(565)	(525)
Property, Plant and Equipment, Net	420	376
Restricted cash collections for securitization trusts	1,259	1,694
Nonmarketable equity securities	938	1,046
Deferred Tax Assets, State Taxes	764	994
Interest Receivable	470	476
Goodwill	240	240
Cash reserve deposits held for securitization trusts	143	184
Accounts and Other Receivables, Net, Current	115	100
Restricted Cash and Cash Equivalents	113	111
Cash and securities collateral placed with counterparties	103	167
Derivative Asset, Fair Value, Gross Asset	41	95
Other Assets, Miscellaneous	1,347	1,371
Other Assets	5,953	6,854
Federal Home Loan Bank Stock	454	577
Federal Reserve Bank Stock	444	435
Insurance Operations Member
Goodwill [Line Items]
Goodwill	27	27
Goodwill	27	27
Corporate and Other [Member]
Goodwill [Line Items]
Goodwill	193	193		$ 193
Goodwill	193	193		$ 193
Automotive Finance Operations [Member]
Goodwill [Line Items]
Goodwill	20	20	$ 20
Goodwill	$ 20	$ 20	$ 20