Rosetta Merger - Assets Acquired and Liabilities Assumed (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions			3 Months Ended				9 Months Ended
	Jul. 20, 2015		Sep. 30, 2016	[1]	Sep. 30, 2015	[1]	Sep. 30, 2016	Sep. 30, 2015	[1]	Dec. 31, 2015
Business Acquisition [Line Items]
Other Noncash Income			$ 0		$ 0		$ 25	$ 0
Shares of Noble Energy common stock issued to Rosetta shareholders (in shares)	41
Rosetta Resources, Inc [Member]
Business Acquisition [Line Items]
Shares of Noble Energy common stock issued to Rosetta shareholders (in shares)	41
Noble Energy common stock price on July 20, 2015	$ 36.97
Fair value of common stock issued	$ 1,518
Plus: Fair value of Rosetta's restricted stock awards and performance awards assumed	10
Plus: Rosetta stock options assumed	1
Total purchase price	1,529
Plus: Liabilities assumed by Noble Energy
Accounts Payable	100
Current Liabilities	37
Long-Term Debt	1,992
Other Long Term Liabilities	23
Asset Retirement Obligation	27
Total purchase price plus liabilities assumed	3,708
Fair Value of Rosetta Assets
Cash and Equivalents	61
Other Current Assets	76
Derivative Instruments	209
Oil and Gas Properties
Proved Reserves	1,613
Undeveloped Leaseholds	1,355
Gathering & Processing Assets	207
Asset Retirement Obligation	27
Other Property Plant and Equipment	5
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Deferred Tax Assets Noncurrent	17
Goodwill	138	[2]								$ 163
Total Asset Value	$ 3,708

[1] Amount relates to an adjustment recorded to the purchase price allocation related to the Rosetta Merger. See Note 5. Rosetta Merger.

[2] As of December 31, 2015, our preliminary purchase price allocation reflected goodwill of $163 million based on the fair value of assets acquired and liabilities assumed at the Rosetta Merger date. In conducting our goodwill impairment test as of December 31, 2015, we determined that our goodwill balance was no longer recoverable and fully impaired it, resulting in a goodwill impairment charge in fourth quarter 2015. In second quarter 2016, we finalized the purchase price allocation and recorded a $25 million gain to Other Operating Expense, Net driven by adjustments made based on the filing of the final Rosetta federal income tax return for the period ending on the Rosetta Merger date.