Finance Receivables - Credit Risk Profile by Dealer grouping of Commercial Finance Receivables (Details) (Commercial Finance Receivables [Member], USD $) In Millions, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014	Mar. 31, 2014	Dec. 31, 2013
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	$ 7,607	$ 8,072	$ 7,108	$ 6,700
Group I
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	954	1,062
Group II
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	2,149	2,090
Group III
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	2,690	2,856
Group IV
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	1,108	1,250
Group V
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	515	559
Group VI
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	$ 191	$ 255