Basis of Presentation (Unaudited) Backlog and Contract Assets and Liabilities (Details 3) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Change in Contract with Customer, Liability [Abstract]
Contract with Customer, Liability, Revenue Recognized	$ 261	$ 232	$ 1,800	$ 1,500
Revenue from Contract with Customer [Abstract]
Revenue, Remaining Performance Obligation, Amount	$ 74,800		$ 74,800
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Explanation			Of our September 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.