Merger, Acquisitions, and Divestitures Merger, Acquisitions and Divestitures - Merger (Details) - USD ($) $ / shares in Units, $ in Millions		12 Months Ended
	Jul. 20, 2015	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Business Acquisition [Line Items]
Shares of Noble Energy common stock issued to Rosetta shareholders		41,048,240	0
Goodwill at End of Year (2)		$ 0	$ 620	$ 627
Business Acquisition, Pro Forma Information [Abstract]
Business Acquisition, Pro Forma Revenue		3,428	6,112
Business Acquisition, Pro Forma Net Income (Loss)		$ (2,393)	$ 1,607
Business Acquisition, Pro Forma Earnings Per Share, Basic		$ (5.64)	$ 4.01
Business Acquisition, Pro Forma Earnings Per Share, Diluted		$ (5.64)	$ 3.94
Rosetta Resources, Inc
Business Acquisition [Line Items]
Shares of Noble Energy common stock issued to Rosetta shareholders	41,000,000
Noble Energy common stock price on July 20, 2015 (in dollars per share)	$ 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
Accounts Payable	100
Current Liabilities	37
Long-Term Deferred Tax Liability	8
Long-Term Debt	1,992
Other Long Term Liabilities	23
Asset Retirement Obligation	27
Total purchase price plus liabilities assumed	3,716
Cash and Equivalents	61
Other Current Assets	76
Derivative Instruments	209
Proved Properties	1,613
Undeveloped Leaseholds	1,355
Gathering and Processing Assets	207
Asset Retirement Obligation	27
Other Property Plant and Equipment	5
Goodwill at End of Year (2)	163
Total Asset Value	$ 3,716