Variable Interest Entities - Assets and Liabilities (Details) - USD ($) $ in Millions	Jun. 30, 2015	Dec. 31, 2014
Variable Interest Entity [Line Items]
Assets	$ 55,330	$ 47,724
Liabilities	47,827	40,332
Finance receivables, net	34,385	33,000
Secured debt	26,617	25,214
Other VIE [Member]
Variable Interest Entity [Line Items]
Assets	3,585	3,696
Liabilities	2,872	3,184
Finance receivables, net	3,200	3,600
Secured debt	$ 2,100	$ 2,500