Basis of Presentation (Unaudited) (Details 2) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Change in Contract with Customer, Liability [Abstract]
Contract with Customer, Liability, Revenue Recognized	$ 333	$ 364	$ 1,000	$ 1,100
Revenue from Contract with Customer [Abstract]
Revenue, Remaining Performance Obligation, Amount	$ 63,000		$ 63,000
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Explanation			We expect to recognize approximately 40 percent and 65 percent of our June 30, 2019 backlog as revenue over the next 12 and 24 months, respectively, with the remainder to be recognized thereafter.