Revenue Recognition Contract Assets (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Mar. 31, 2020	Dec. 31, 2019	Mar. 31, 2019	Dec. 31, 2018
Revenue Recognition [Abstract]
Contract with Customer, Asset, after Allowance for Credit Loss	$ 30	$ 17	$ 30	$ 17	$ 18	$ 8	$ 22	$ 4
Contract with Customer, Asset, Cumulative Catch-up Adjustment to Revenue, Change in Measure of Progress	46	20	69	39
Contract with Customer, Asset, Reclassified to Receivable	$ (34)	$ (25)	$ (47)	$ (26)