Basis of Presentation (Unaudited) (Details 2) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Change in Contract with Customer, Liability [Abstract]
Contract with Customer, Liability, Revenue Recognized	$ 674	$ 706
Revenue from Contract with Customer [Abstract]
Revenue, Remaining Performance Obligation, Amount	$ 57,300
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Explanation	We expect to recognize approximately 50 percent and 75 percent of our March 31, 2019 backlog as revenue over the next 12 and 24 months, respectively, with the remainder to be recognized thereafter.