Finance Receivables - Credit Risk Profile by Dealer grouping of Commercial Finance Receivables (Details) - Commercial Finance Receivables [Member] - USD ($) $ in Millions	Jun. 30, 2015	Dec. 31, 2014	Jun. 30, 2014	Dec. 31, 2013
Accounts, Notes, Loans and Financing Receivable [Line Items]
Balance at end of period	$ 7,815	$ 8,072	$ 7,114	$ 6,700
Group I
Accounts, Notes, Loans and Financing Receivable [Line Items]
Balance at end of period	1,068	1,062
Group II
Accounts, Notes, Loans and Financing Receivable [Line Items]
Balance at end of period	2,415	2,090
Group III
Accounts, Notes, Loans and Financing Receivable [Line Items]
Balance at end of period	2,617	2,856
Group IV
Accounts, Notes, Loans and Financing Receivable [Line Items]
Balance at end of period	1,071	1,250
Group V
Accounts, Notes, Loans and Financing Receivable [Line Items]
Balance at end of period	443	559
Group VI
Accounts, Notes, Loans and Financing Receivable [Line Items]
Balance at end of period	$ 201	$ 255