Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Millions			3 Months Ended		9 Months Ended
		Jul. 20, 2015	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Earnings Per Share [Abstract]
Net Income (Loss)			$ (283)	$ 419	$ (413)	$ 811
Earnings Adjustment from Assumed Conversion of Dilutive Shares of Common Stock in Rabbi Trust			0	(8)	0	0
Net Income (Loss) Used for Diluted Earnings Per Share Calculation			$ (283)	$ 411	$ (413)	$ 811
Weighted Average Number of Shares Outstanding, Basic (in shares)	[1]		420,000,000	362,000,000	392,000,000	361,000,000
Incremental Shares from Assumed Conversion of Dilutive Stock Options, Restricted Stock, and Shares of Common Stock in Rabbi Trust (in shares)	[2]		0	5,000,000	0	6,000,000
Weighted Average Number of Shares Outstanding, Diluted (in shares)			420,000,000	367,000,000	392,000,000	367,000,000
Earnings (Loss) from Continuing Operations Per Share, Basic (in dollars per share)			$ (0.67)	$ 1.16	$ (1.05)	$ 2.25
Earnings (Loss) from Continuing Operations Per Share, Diluted (in dollars per share)			$ (0.67)	$ 1.12	$ (1.05)	$ 2.21
Number of antidilutive stock options, shares of restricted stock and shares of common stock in rabbi trust excluded from calculation above (in shares)			14,000,000	2,000,000	11,000,000	3,000,000
Underwritten public offering (in shares)					24,150,000
Shares exchange in acquisition		41,000,000

[1] The weighted average number of shares outstanding includes the weighted average shares of common stock issued in connection with the underwritten public offering of 24.15 million shares of Noble Energy common stock in first quarter 2015 and issued in connection with the exchange of approximately 41 million shares for all outstanding shares of Rosetta common stock on July 20, 2015.

[2] For the three and nine months ended September 30, 2015, all outstanding options and non-vested restricted shares have been excluded from the calculation of diluted EPS as Noble Energy incurred losses. Therefore, inclusion of outstanding options and non-vested restricted shares in the calculation of diluted EPS would be anti-dilutive. Consistent with GAAP, when dilutive, deferred compensation gains or losses, net of tax, are excluded from net income while our common shares held in the rabbi trust are included in the diluted share count. For this reason, the diluted earnings per share calculations for the three months ended September 30, 2014 excluded deferred compensation (gains) losses, net of tax. The deferred compensation loss, net of tax, excluded for the calculation of diluted earnings per share for the nine months ended September 30, 2014 was de minimis.