Fair Value Measurements (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Financial Assets:
Financial Assets: Crude Oil Swaps		$ 100
Financial Liabilities:
Financial Liabilities: Crude Oil Swaps		121
Financial Liabilities: Crude Oil Options/Swaptions		244
Proved oil and gas properties, other property, plant and equipment and other assets, carrying amount	$ 9,154	968
Proved oil and gas properties, other property, plant and equipment and other assets written down during the period - fair value at end of period	2,828	393
Pretax impairment charges for proved oil and gas properties, other property, plant and equipment and other assets	6,326	575
Net of Tax Impairment Charges for Proved Oil and Gas Properties, Other Property, Plant and Equipment and Other Assets	4,141
Pretax impairment charges for proved oil and gas properties and other assets, in which EOG utilized an accepted offer from a third-party purchaser		58
Aggregate Principal Amount of Current and Long-Term Debt	6,390	5,890
Fair Value of Debt	$ 6,524	6,242
Fair Value, Inputs, Level 1 [Member]
Financial Assets:
Financial Assets: Crude Oil Swaps		0
Financial Liabilities:
Financial Liabilities: Crude Oil Swaps		0
Financial Liabilities: Crude Oil Options/Swaptions		0
Fair Value, Inputs, Level 2 [Member]
Financial Assets:
Financial Assets: Crude Oil Swaps		100
Financial Liabilities:
Financial Liabilities: Crude Oil Swaps		121
Financial Liabilities: Crude Oil Options/Swaptions		244
Fair Value, Inputs, Level 3 [Member]
Financial Assets:
Financial Assets: Crude Oil Swaps		0
Financial Liabilities:
Financial Liabilities: Crude Oil Swaps		0
Financial Liabilities: Crude Oil Options/Swaptions		$ 0