Interest And Other Income (Interest And Other Income) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Other Income and Expenses [Abstract]
Tax refunds	$ 13	$ 6	$ 1
Deferred Compensation Plan Income	7	15	(2)
Other Interest and Dividend Income	5	17	29
Seismic Data Sales	2	5	5
Gain (Loss) on Disposition of Assets	0	56	0
Contingent Consideration, Valuation Adjustment	(42)	(45)	0
Investment in affiliate valuation adjustment	(64)	15	0
Other Income	12	7	5
Interest and other	$ (67)	$ 76	$ 38