Variable Interest Entities - Assets and Liabilities (Details) - USD ($) $ in Millions	Sep. 30, 2016	Dec. 31, 2015
Variable Interest Entity [Line Items]
Assets	$ 82,111	$ 65,904
Liabilities	73,493	57,852
Finance receivables, net	41,132	36,781
Secured debt (Note 7; Note 8 VIEs)	35,237	30,689
Other VIE [Member]
Variable Interest Entity [Line Items]
Assets	4,617	3,652
Liabilities	3,881	2,941
Finance receivables, net	3,600	3,200
Secured debt (Note 7; Note 8 VIEs)	$ 2,900	$ 2,600