Consolidated Statements of Equity - USD ($) $ in Millions	Total	Common Stock	Additional Paid in Capital	Accumulated Other Comprehensive Loss	Treasury Stock at Cost	Retained Earnings	Non- controlling Interests
Balance at Beginning of Period at Dec. 31, 2016	$ 9,600	$ 5	$ 6,450	$ (31)	$ (692)	$ 3,556	$ 312
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	47					36	11
Stock-based Compensation	13		13
Dividends (10 cents per share)	(44)					(44)
Distributions to Noncontrolling Interest Owners	(6)						(6)
Other	(1)		9		(11)	1
Balance at End of Period at Mar. 31, 2017	9,609	5	6,472	(31)	(703)	3,549	317
Balance at Beginning of Period at Dec. 31, 2017	10,619	5	8,438	(30)	(725)	2,248	683
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	574					554	20
Stock-based Compensation	17		17
Dividends (10 cents per share)	(48)					(48)
Purchase and Retirement of Common Stock	(67)		(67)
Clayton Williams Energy Acquisition	(25)		(25)
Contributions from Noncontrolling Interest Owners	331						331
Distributions to Noncontrolling Interest Owners	(11)						(11)
Other	(3)			1	(6)		2
Balance at End of Period at Mar. 31, 2018	$ 11,387	$ 5	$ 8,363	$ (29)	$ (731)	$ 2,754	$ 1,025