Variable Interest Entities - Assets and Liabilities of Other VIE's (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Variable Interest Entity [Line Items]
Assets	$ 87,765	$ 65,904
Liabilities	79,072	57,852
Finance receivables, net	43,190	36,781
Secured debt (Note 8; Note 9 VIEs)	39,270	30,689
Other VIE [Member]
Variable Interest Entity [Line Items]
Assets	4,251	3,652
Liabilities	3,559	2,941
Finance receivables, net	3,500	3,200
Secured debt (Note 8; Note 9 VIEs)	$ 3,000	$ 2,600