Finance Receivables - Credit Risk Profile by Dealer grouping of Commercial Finance Receivables (Details) - Commercial Finance Receivables [Member] - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amount	$ 11,123	$ 8,439	$ 8,072	$ 6,700
Concentration risk (percent)	100.00%	100.00%
Group I [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amount	$ 1,596	$ 1,299
Concentration risk (percent)	14.30%	15.40%
Group II [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amount	$ 3,445	$ 2,648
Concentration risk (percent)	31.00%	31.40%
Group III [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amount	$ 4,039	$ 2,703
Concentration risk (percent)	36.30%	32.00%
Group IV [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amount	$ 1,231	$ 1,100
Concentration risk (percent)	11.10%	13.00%
Group V [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amount	$ 642	$ 505
Concentration risk (percent)	5.80%	6.00%
Group VI [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amount	$ 170	$ 184
Concentration risk (percent)	1.50%	2.20%