Revenue Revenue Remaining Performance Obligation, Expected Timing of Satisfaction (Details) - Extended service contracts - Automotive - Operating Segments [Member] $ in Millions	3 Months Ended
	Mar. 31, 2018 USD ($)
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2018-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue remaining performance obligation expected timing of satisfaction period	1 year
Revenue, Remaining Performance Obligation	$ 900
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2019-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue remaining performance obligation expected timing of satisfaction period	1 year
Revenue, Remaining Performance Obligation	$ 1,000
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue remaining performance obligation expected timing of satisfaction period	8 years
Revenue, Remaining Performance Obligation	$ 3,900