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