Financial Services Finance Receivables Aging (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Financing Receivables [Line Items]
Number Of Days After Which Finance Receivable Is Considered Past Due	31 days
Financing Receivable, Gross	$ 96,674	$ 91,064
Consumer [Member]
Financing Receivables [Line Items]
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing	21	16
Financing Receivable, Recorded Investment, Past Due	947	881
Financing Receivable, Recorded Investment, Current	64,391	59,068
Financing Receivable, Gross	65,338	59,949
Consumer [Member] | Financing Receivables, 31 to 60 Days Past due [Member]
Financing Receivables [Line Items]
Financing Receivable, Recorded Investment, Past Due	760	708
Consumer [Member] | Financing Receivables, 61 to 90 Days Past due [Member]
Financing Receivables [Line Items]
Financing Receivable, Recorded Investment, Past Due	114	108
Consumer [Member] | Financing Receivables, 91 to 120 Days Past due [Member]
Financing Receivables [Line Items]
Financing Receivable, Recorded Investment, Past Due	34	27
Consumer [Member] | Financing Receivables, Greater than 120 Days Past due [Member]
Financing Receivables [Line Items]
Financing Receivable, Recorded Investment, Past Due	39	38
Non-consumer [Member]
Financing Receivables [Line Items]
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing	0	1
Financing Receivable, Recorded Investment, Past Due	107	116
Financing Receivable, Recorded Investment, Current	31,229	30,999
Financing Receivable, Gross	$ 31,336	$ 31,115