Basis of Presentation (Unaudited) Backlog and Contract Assets and Liabilities (Details 3) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Change in Contract with Customer, Liability [Abstract]
Contract with Customer, Liability, Revenue Recognized	$ 482	$ 442	$ 1,500	$ 1,200
Revenue from Contract with Customer [Abstract]
Revenue, Remaining Performance Obligation, Amount	$ 76,600		$ 76,600
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Explanation			Of our June 30, 2021 backlog, we expect to recognize approximately 40 percent as revenue over the next 12 months and 60 percent as revenue over the next 24 months, with the remainder to be recognized thereafter.