Income Per Share Attributable to Noble Energy (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Earnings Per Share [Abstract]
Net Loss and Comprehensive Loss Attributable to Noble Energy	$ 227	$ (136)	$ 758	$ (1,612)
Weighted Average, Number of Shares Outstanding, Basic (in shares)	482	487	484	464
Incremental Shares from Assumed Conversion of Dilutive Stock Options, Restricted Stock, and Shares of Common Stock in Rabbi Trust (in shares)	2	0	2	0
Weighted Average, Number of Shares Outstanding, Diluted (in shares)	484	487	486	464
Loss Per Share, Basic ($ per share)	$ 0.47	$ (0.28)	$ 1.57	$ (3.47)
Loss Per Share, Diluted ($ per share)	$ 0.47	$ (0.28)	$ 1.56	$ (3.47)
Number of Antidilutive Stock Options, Shares of Restricted Stock, and Shares of Common Stock in Rabbi Trust Excluded from Calculation Above (in shares)	13	16	14	16