Net (Loss) Income Per Share Attributable to Noble Energy Common Shareholders (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Earnings Per Share [Abstract]
Net Loss and Comprehensive Loss Attributable to Noble Energy	$ (10)	$ (23)	$ (323)	$ 531
Weighted Average, Number of Shares Outstanding, Basic (in shares)	478	484	478	485
Incremental Shares from Assumed Conversion of Dilutive Stock Options, Restricted Stock, and Shares of Common Stock in Rabbi Trust (in shares)	0	0	0	2
Weighted Average, Number of Shares Outstanding, Diluted (in shares)	478	484	478	487
(Loss) Income Per Share, Basic ($ per share)	$ (0.02)	$ (0.05)	$ (0.68)	$ 1.09
(Loss) Income Per Share, Diluted ($ per share)	$ (0.02)	$ (0.05)	$ (0.68)	$ 1.09
Number of Antidilutive Stock Options, Shares of Restricted Stock, and Shares of Common Stock in Rabbi Trust Excluded from Calculation Above (in shares)	15	14	15	14
Share purchase plan, authorized amount	$ 750		$ 750