Net Income (Loss) Per Share Attributable to Noble Energy Common Shareholders (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Earnings Per Share [Abstract]
Net Income (Loss) and Comprehensive Income (Loss) Attributable to Noble Energy	$ 17	$ 227	$ (306)	$ 758
Weighted Average, Number of Shares Outstanding, Basic (in shares)	478	482	478	484
Incremental Shares from Assumed Conversion of Dilutive Stock Options, Restricted Stock, and Shares of Common Stock in Rabbi Trust (in shares)	2	2	0	2
Weighted Average, Number of Shares Outstanding, Diluted (in shares)	480	484	478	486
(Loss) Income Per Share, Basic ($ per share)	$ 0.04	$ 0.47	$ (0.64)	$ 1.57
(Loss) Income Per Share, Diluted ($ per share)	$ 0.04	$ 0.47	$ (0.64)	$ 1.56
Number of Antidilutive Stock Options, Shares of Restricted Stock, and Shares of Common Stock in Rabbi Trust Excluded from Calculation Above (in shares)	14	13	15	14
Share purchase plan, authorized amount	$ 750		$ 750