Financial Services Finance Receivables - Impaired (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
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	$ 359	$ 370
Impaired Financing Receivable Recorded Investment, Percentage of Receivable	0.50%	0.50%
Non-consumer [Member]
Financing Receivable Impaired [Line Items]
Impaired Financing Receivable, Recorded Investment	$ 124	$ 129
Impaired Financing Receivable Recorded Investment, Percentage of Receivable	0.30%	0.40%