Other Assets (Schedule of Other Assets) (Details) - USD ($) $ in Millions	Mar. 31, 2017	Dec. 31, 2016	Aug. 01, 2016	Jun. 01, 2016
Goodwill [Line Items]
Goodwill	$ 240	$ 240
Property, Plant and Equipment, Gross	939	901
Accumulated depreciation	(542)	(525)
Property, Plant and Equipment, Net	397	376
Restricted cash collections for securitization trusts	1,359	1,694
Deferred Tax Assets, State Taxes	900	994
Nonmarketable equity investments	833	1,046
Interest Receivable	457	476
Goodwill	240	240
Accounts and Other Receivables, Net, Current	165	100
Cash reserve deposits held for securitization trusts	164	184
Cash and securities collateral placed with counterparties	119	167
Restricted Cash and Cash Equivalents	111	111
Derivative Asset, Fair Value, Gross Asset	80	95
Other Assets, Miscellaneous	1,309	1,371
Other Assets	6,134	6,854
Federal Home Loan Bank Stock	359	577
Federal Reserve Bank Stock	435	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