Other Assets (Schedule of Other Assets) (Details) - USD ($) $ in Millions	Dec. 31, 2016	Aug. 01, 2016	Jun. 01, 2016	Dec. 31, 2015
Goodwill [Line Items]
Goodwill	$ 240			$ 27
Property, Plant and Equipment, Gross	901			691
Accumulated depreciation	(525)			(456)
Property, Plant and Equipment, Net	376			235
Restricted cash collections for securitization trusts	1,694			2,010
Nonmarketable equity investments	1,046			418
Deferred Tax Assets, State Taxes	994			1,369
Interest Receivable	476			402
Goodwill	240			27
Cash reserve deposits held for securitization trusts	184			252
Cash and securities collateral placed with counterparties	167			125
Restricted Cash and Cash Equivalents	111			120
Other accounts receivable	100			158
Derivative Asset, Fair Value, Gross Asset	95			233
Other Assets, Miscellaneous	1,371			972
Other Assets	6,854			6,321
Federal Home Loan Bank Stock	577			391
Federal Reserve Bank Stock	435			0
Insurance Operations Member
Goodwill [Line Items]
Goodwill	27			27
Goodwill	27			27
Corporate and Other [Member]
Goodwill [Line Items]
Goodwill	193		$ 193	0
Goodwill	193		$ 193	0
Automotive Finance Operations [Member]
Goodwill [Line Items]
Goodwill	20	$ 20		0
Goodwill	$ 20	$ 20		$ 0