Acquisitions and Divestitures - Pro Forma Information (Details) - Clayton Williams Energy - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Business Acquisition [Line Items]
Revenues	$ 4,986	$ 4,304	$ 3,651
Net Loss Attributable to Noble Energy	$ (66)	$ (678)	$ (1,082)
Net Income (Loss) Attributable to Noble Energy per Common Share
Basic (in usd per share)	$ (0.14)	$ (1.39)	$ (2.23)
Diluted (in usd per share)	$ (0.14)	$ (1.39)	$ (2.23)