Rosetta Merger - Assets Acquired and Liabilities Assumed (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	Jul. 20, 2015	Sep. 30, 2015	Dec. 31, 2014
Business Acquisition [Line Items]
Shares of Noble Energy common stock issued to Rosetta shareholders (in shares)	41
Oil and Gas Properties:
Goodwill		$ 945	$ 620
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	$ 1,516
Plus: fair value of Rosetta's restricted stock awards and performance awards assumed	11
Plus: Rosetta stock options assumed	1
Total purchase price	1,528
Plus: liabilities assumed by Noble Energy
Accounts Payable	96
Current Liabilities	37
Long-Term Debt	1,992
Other Long Term Liabilities	24
Asset Retirement Obligation	27
Total purchase price plus liabilities assumed	3,704
Fair Value of Rosetta Assets
Cash and Equivalents	61
Other Current Assets	74
Derivative Instruments	209
Oil and Gas Properties:
Proved Reserves	1,541
Undeveloped Leaseholds	1,165
Gathering & Processing Assets	207
Asset Retirement	27
Other Property Plant & Equipment	5
Long Term Deferred Tax Asset	86
Goodwill	329
Total Asset Value	$ 3,704