Finance Receivables - Aging (Details) - Financial Services [Member] - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2015	Dec. 31, 2014	Sep. 30, 2014
Financing Receivables [Line Items]
Number Of Days After Which Finance Receivable Is Considered Past Due	any payment, including principal and interest, that is at least 31 days past the contractual due date
Financing Receivable, Gross	$ 92,324	$ 86,462	$ 84,862
Minimum [Member]
Financing Receivables [Line Items]
Number Of Days At Which Finance Receivables Are In Process Of Collection	90 days
Consumer [Member]
Financing Receivables [Line Items]
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing	$ 15	17
Financing Receivable Recorded Investment 31 To 60 Days Past Due	597	718
Financing Receivable Recorded Investment 61 To 90 Days Past Due	94	97
Financing Receivable Recorded Investment 91 To 120 Days Past Due	25	29
Financing Receivable Recorded Investment Greater Than 120 Days Past Due	39	52
Financing Receivable, Recorded Investment, Past Due	755	896
Financing Receivable, Recorded Investment, Current	58,369	53,200
Financing Receivable, Gross	59,124	54,096
Non-consumer [Member]
Financing Receivables [Line Items]
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing	3	3
Financing Receivable, Recorded Investment, Past Due	127	117
Financing Receivable, Recorded Investment, Current	33,073	32,249
Financing Receivable, Gross	$ 33,200	$ 32,366