Variable Interest Entities - Assets and Liabilities (Details) - USD ($) $ in Millions	Sep. 30, 2015	Dec. 31, 2014
Variable Interest Entity [Line Items]
Assets	$ 59,546	$ 47,724
Liabilities	52,142	40,332
Finance receivables, net	35,074	33,000
Secured debt	28,284	25,214
Other VIE [Member]
Variable Interest Entity [Line Items]
Assets	3,690	3,696
Liabilities	2,969	3,184
Finance receivables, net	3,200	3,600
Secured debt	$ 2,600	$ 2,500