Financial Services Finance Receivables - Impaired (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2017	Dec. 31, 2016
Financing Receivable Impaired [Line Items]
Number of Days Past Due After Which Consumer Receivables are Considered Impaired	120 days
Consumer [Member]
Financing Receivable Impaired [Line Items]
Impaired Financing Receivable, Recorded Investment	$ 387	$ 367
Impaired Financing Receivable Recorded Investment, Percentage of Receivable	0.50%	0.60%
Non-consumer [Member]
Financing Receivable Impaired [Line Items]
Impaired Financing Receivable, Recorded Investment	$ 152	$ 107
Impaired Financing Receivable Recorded Investment, Percentage of Receivable	0.50%	0.30%