Finance Receivables - Credit Risk Profile by Dealer grouping of Commercial Finance Receivables (Details) - Commercial Finance Receivables [Member] - USD ($) $ in Millions	Mar. 31, 2016	Dec. 31, 2015	Mar. 31, 2015	Dec. 31, 2014
Accounts, Notes, Loans and Financing Receivable [Line Items]
Balance at end of period	$ 9,229	$ 8,439	$ 7,607	$ 8,072
Group I
Accounts, Notes, Loans and Financing Receivable [Line Items]
Balance at end of period	1,318	1,299
Group II
Accounts, Notes, Loans and Financing Receivable [Line Items]
Balance at end of period	2,881	2,648
Group III
Accounts, Notes, Loans and Financing Receivable [Line Items]
Balance at end of period	3,001	2,703
Group IV
Accounts, Notes, Loans and Financing Receivable [Line Items]
Balance at end of period	1,249	1,100
Group V
Accounts, Notes, Loans and Financing Receivable [Line Items]
Balance at end of period	630	505
Group VI
Accounts, Notes, Loans and Financing Receivable [Line Items]
Balance at end of period	$ 150	$ 184