Variable Interest Entities - Assets and Liabilities (Details) - USD ($) $ in Millions	Mar. 31, 2016	Dec. 31, 2015
Variable Interest Entity [Line Items]
Assets	$ 72,764	$ 65,904
Liabilities	64,389	57,852
Finance receivables, net	38,658	36,781
Secured debt	32,733	30,689
Other VIE [Member]
Variable Interest Entity [Line Items]
Assets	4,422	3,652
Liabilities	3,677	2,941
Finance receivables, net	3,500	3,200
Secured debt	$ 2,900	$ 2,600