Stock-Based Compensation (Details) - USD ($) $ / shares in Units, $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Stock Options/SARs and Employee Stock Purchase Plan (ESPP) Disclosures [Line Items]
Compensation expense related to the company's stock-based compensation plans		$ 43.5	$ 37.6	$ 101.5	$ 97.1
Stock-based compensation expense related to stock options, SAR and ESPP grants		$ 20.9	$ 18.8	$ 42.9	$ 45.0
Common Shares Available for Grant		17,100,000		17,100,000
Unrecognized compensation expense		$ 110.3		$ 110.3
Weighted average period over which unrecognized compensation expense will be recognized (in years)				2 years 8 months 12 days
Stock Options and SARs [Member]
Weighted Average Fair Values And Valuation Assumptions Used To Value Stock Option/SARs, ESPP, and Performance Units/Stock Stock-Based Compensation [Abstract]
Weighted Average Fair Value of Grants (price per share)				$ 23.94	$ 25.77
Expected Volatility (in hundredths)				28.28%	31.52%
Risk-Free Interest Rate (in hundredths)				1.52%	0.78%
Dividend Yield (in hundredths)				0.75%	0.76%
Expected Life (in years)				5 years 1 month 6 days	5 years 4 months 24 days
Stock Options and SARs Rollforward [Abstract]
Outstanding at January 1 (in shares)				9,850,000	10,744,000
Granted (in shares)				2,260,000	1,821,000
Exercised (1) (in shares)	[1]			(1,674,000)	(1,673,000)
Forfeited (in shares)				(269,000)	(241,000)
Outstanding at September 30 (2) (in shares)	[2]	10,167,000	10,651,000	10,167,000	10,651,000
Stock Options and SARs Vested or Expected to Vest (in shares)	[3]	9,799,000	10,300,000	9,799,000	10,300,000
Stock Options and SARs Exercisable at September 30 (in shares)	[4]	5,517,000	6,302,000	5,517,000	6,302,000
Intrinsic Value of Stock Options/SARs Exercised				$ 66.6	$ 58.7
Intrinsic Value of Stock Options/SARs Outstanding		$ 147.8	$ 240.8	$ 147.8	$ 240.8
Weighted Average Remaining Contractual Life for Stock Options/SARs Outstanding				4 years 3 months 18 days	4 years 1 month 6 days
Intrinsic Value of Stock Options/SARs Vested or Expected to Vest		145.9	237.2	$ 145.9	$ 237.2
Weighted average remaining contractual life for stock options/SARs vested or expected to vest (in years)al Term				4 years 3 months 18 days	4 years
Aggregate Intrinsic Value for Exercisable Units		$ 123.2	$ 196.3	$ 123.2	$ 196.3
Weighted average remaining contractual life for exercisable options/SARs (in years)				2 years 9 months 18 days	2 years 9 months 18 days
Weighted Average Grant Price Stock Option and SARs [Rollforward]
Outstanding at January 1 (price per share)				$ 75.53	$ 67.98
Granted (price per share)				96.24	94.87
Exercised (1) (price per share)	[1]			55.63	49.85
Forfeited (price per share)				90.22	85.77
Outstanding at September 30 (2) (price per share)	[2]	$ 83.02	$ 75.02	83.02	75.02
Vested or Expected to Vest (3) (price per share)	[3]	82.69	74.60	82.69	74.60
Exercisable at September 30 (4) (price per share)	[4]	$ 75.59	$ 66.46	75.59	66.46
ESPP [Member]
Weighted Average Fair Values And Valuation Assumptions Used To Value Stock Option/SARs, ESPP, and Performance Units/Stock Stock-Based Compensation [Abstract]
Weighted Average Fair Value of Grants (price per share)				$ 22.10	$ 19.28
Expected Volatility (in hundredths)				26.96%	36.54%
Risk-Free Interest Rate (in hundredths)				0.89%	0.43%
Dividend Yield (in hundredths)				0.71%	0.82%
Expected Life (in years)				6 months	6 months
Restricted Stock And Restricted Stock Units [Member]
Stock Options/SARs and Employee Stock Purchase Plan (ESPP) Disclosures [Line Items]
Unrecognized compensation expense		$ 191.2		$ 191.2
Weighted average period over which unrecognized compensation expense will be recognized (in years)				2 years 7 months 6 days
Restricted Stock/Restricted Stock Units [Roll Forward]
Share-Based Compensation Arrangement By Restricted Stock And Restricted Stock Units Compensation Cost		$ 15.8	$ 13.1	$ 50.0	$ 45.5
Outstanding at January 1 (in shares)				3,962,000	4,908,000
Granted (in shares)				1,061,000	833,000
Released (1) (in shares)	[5]			(837,000)	(1,392,000)
Forfeited (in shares)				(190,000)	(269,000)
Outstanding at September 30 (2) (in shares)	[6]	3,996,000	4,080,000	3,996,000	4,080,000
Weighted Average Grant Price Restricted Stock and Restricted Stock Units [Roll Forward]
Outstanding at January 1 (price per share)				$ 79.63	$ 70.35
Granted (price per share)				97.26	87.76
Released (1) (price per share)	[5]			59.67	53.15
Forfeited (price per share)				84.66	76.40
Outstanding at September 30 (2) (price per share)	[6]	$ 88.25	$ 79.37	$ 88.25	$ 79.37
Performance Units and Performance Stock Disclosures [Abstract]
Intrinsic value released during the year				$ 81.6	$ 116.3
Aggregate intrinsic value of stock and units outstanding		$ 386.6	$ 394.6	386.6	394.6
Performance Units and Performance Stock [Member]
Stock Options/SARs and Employee Stock Purchase Plan (ESPP) Disclosures [Line Items]
Compensation expense related to the company's stock-based compensation plans		6.8	5.7	8.6	$ 6.6
Unrecognized compensation expense		$ 9.4		$ 9.4
Weighted average period over which unrecognized compensation expense will be recognized (in years)				2 years 3 months 18 days
Weighted Average Fair Values And Valuation Assumptions Used To Value Stock Option/SARs, ESPP, and Performance Units/Stock Stock-Based Compensation [Abstract]
Weighted Average Fair Value of Grants (price per share)				$ 113.81	$ 112.09
Expected Volatility (in hundredths)				32.19%	32.01%
Risk-Free Interest Rate (in hundredths)				1.60%	0.89%
Restricted Stock/Restricted Stock Units [Roll Forward]
Outstanding at January 1 (in shares)				545,290
Granted (in shares)				78,527
Released (1) (in shares)	[5]			240,320
Outstanding at September 30 (2) (in shares)		502,331		502,331
Performance Units and Performance Stock Disclosures [Abstract]
Performance Period for Performance Units and Shares				3 years
Additional Performance Awards Granted				118,834
Minimum Performance Multiple at the Completion of the Performance Period				0.00%
Maximum Performance Multiple at the Completion of the Performance Period				200.00%
Maximum Performance Units and Stock Allowed to be Outstanding				856,218
Minimum Performance Units and Stock Allowed to be Outstanding				148,444
Intrinsic value released during the year				$ 23.6
Aggregate intrinsic value of stock and units outstanding		$ 48.6		$ 48.6
Term Of Zero- Coupon Risk- Free Interest Rate In Years Derived From Treasury Constant Maturities Yield Curve				3 years 3 months 7 days
Lease And Well [Member]
Stock Options/SARs and Employee Stock Purchase Plan (ESPP) Disclosures [Line Items]
Compensation expense related to the company's stock-based compensation plans		9.5	8.9	$ 30.0	$ 28.2
Gathering And Processing Costs [Member]
Stock Options/SARs and Employee Stock Purchase Plan (ESPP) Disclosures [Line Items]
Compensation expense related to the company's stock-based compensation plans		0.1	0.4	0.5	1.0
Exploration Costs [Member]
Stock Options/SARs and Employee Stock Purchase Plan (ESPP) Disclosures [Line Items]
Compensation expense related to the company's stock-based compensation plans		4.7	4.1	16.1	15.6
General And Administrative [Member]
Stock Options/SARs and Employee Stock Purchase Plan (ESPP) Disclosures [Line Items]
Compensation expense related to the company's stock-based compensation plans		$ 29.2	$ 24.2	$ 54.9	$ 52.3

[1] The total intrinsic value of stock options/SARs exercised for the nine months ended September 30, 2017 and 2016 was $66.6 million and $58.7 million, respectively. The intrinsic value is based upon the difference between the market price of EOG's common stock on the date of exercise and the grant price of the stock options/SARs.

[2] The total intrinsic value of stock options/SARs outstanding at September 30, 2017 and 2016 was $147.8 million and $240.8 million, respectively. At September 30, 2017 and 2016, the weighted average remaining contractual life was 4.3 years and 4.1 years, respectively.

[3] The total intrinsic value of stock options/SARs vested or expected to vest at September 30, 2017 and 2016 was $145.9 million and $237.2 million, respectively. At September 30, 2017 and 2016, the weighted average remaining contractual life was 4.3 years and 4.0 years, respectively.

[4] The total intrinsic value of stock options/SARs exercisable at September 30, 2017 and 2016 was $123.2 million and $196.3 million, respectively. At September 30, 2017 and 2016, the weighted average remaining contractual life was 2.8 years and 2.8 years, respectively.

[5] The total intrinsic value of restricted stock and restricted stock units released for the nine months ended September 30, 2017 and 2016 was $81.6 million and $116.3 million, respectively. The intrinsic value is based upon the closing price of EOG's common stock on the date the restricted stock and restricted stock units are released.

[6] The total intrinsic value of restricted stock and restricted stock units outstanding at September 30, 2017 and 2016 was $386.6 million and $394.6 million, respectively.