Oil and Gas Exploration and Production Industries Disclosures (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014 MBoe		Dec. 31, 2013 MBoe		Dec. 31, 2012 MBoe		Dec. 31, 2011 MBoe
Proved Developed And Undeveloped Reserves (MBoe) [Rollforward]
Net proved reserves - beginning of period (MBoe)	2,118,543		1,810,698		2,053,763
Revisions of previous estimates	100,568		108,990		(392,621)
Purchases in place	14,367		3,241		4,098
Extensions, discoveries and other additions	519,167		398,965		406,932
Sales in place	(36,263)		(15,375)		(90,420)
Production	(219,126)		(187,976)		(171,054)
Net proved reserves - end of period (MBoe)	2,497,256		2,118,543		1,810,698
Net Proved Developed and Undeveloped Reserves [Abstract]
Net proved developed reserves (MBOE)	1,347,947		1,127,476		949,819		1,042,713
Net proved undeveloped reserve (MBOE)	1,149,309		991,067		860,879		1,011,050
Revisions of previous estimates	100,568		108,990		(392,621)
Capitalized Costs, Oil and Gas Producing Activities, Gross [Abstract]
Proved properties	$ 45,169,101		$ 41,377,303
Unproved properties	1,334,431		1,444,500
Total	46,503,532		42,821,803
Accumulated depreciation, depletion and amortization	(20,212,748)		(18,880,611)
Net capitalized costs	$ 26,290,784		$ 23,941,192
Crude Oil (MBbl) [Member]
Proved Developed and Undeveloped Reserves [Rollforward]
Net proved reserves - beginning of period	900,540		700,818		517,493
Revisions of previous estimates	28,022		50,669		1,688
Purchases in place	9,705		1,097		1,010
Extensions, discoveries and other additions	319,554		230,754		255,686
Sales in place	(12,623)		(2,337)		(17,264)
Production	(105,448)		(80,461)		(57,795)
Net proved reserves - end of period	1,139,750		900,540		700,818
Net Proved Developed and Undeveloped Reserves [Abstract]
Net proved developed reserves	495,148		391,056		290,650		224,755
Net proved undeveloped reserves	644,602		509,484		410,168		292,738
Natural Gas Liquids (MBbl) [Member]
Proved Developed and Undeveloped Reserves [Rollforward]
Net proved reserves - beginning of period	377,206		319,963		227,788
Revisions of previous estimates	27,443		12,109		47,856
Purchases in place	1,812		1,202		612
Extensions, discoveries and other additions	91,683		69,197		71,574
Sales in place	(1,779)		(1,471)		(7,377)
Production	(29,297)		(23,794)		(20,490)
Net proved reserves - end of period	467,068		377,206		319,963
Net Proved Developed and Undeveloped Reserves [Abstract]
Net proved developed reserves	264,749		200,860		162,593		125,363
Net proved undeveloped reserves	202,319		176,346		157,370		102,425
Natural Gas (MMcf) [Member]
Proved Developed and Undeveloped Reserves [Rollforward]
Net proved reserves - beginning of period	5,044,800		4,739,500		7,850,900
Revisions of previous estimates	270,600		277,300		(2,653,000)
Purchases in place	17,100		5,700		14,800
Extensions, discoveries and other additions	647,500		594,100		478,100
Sales in place	(131,100)		(69,400)		(394,700)
Production	(506,300)		(502,400)		(556,600)
Net proved reserves - end of period	5,342,600		5,044,800		4,739,500
Net Proved Developed and Undeveloped Reserves [Abstract]
Net proved developed reserves	3,528,300		3,213,400		2,979,500		4,155,600
Net proved undeveloped reserves	1,814,300		1,831,400		1,760,000		3,695,300
United States [Member]
Proved Developed And Undeveloped Reserves (MBoe) [Rollforward]
Net proved reserves - beginning of period (MBoe)	1,989,166	[1]	1,662,108	[1]	1,729,508	[1]
Revisions of previous estimates	97,782	[1]	113,823	[1]	(237,936)	[1]
Purchases in place	14,367	[1]	3,241	[1]	4,098	[1]
Extensions, discoveries and other additions	517,613	[1]	383,324	[1]	392,196	[1]
Sales in place	(14,661)	[1]	(15,375)	[1]	(87,588)	[1]
Production	(190,065)	[1]	(157,955)	[1]	(138,170)	[1]
Net proved reserves - end of period (MBoe)	2,414,202	[1]	1,989,166	[1]	1,662,108	[1]
Net Proved Developed and Undeveloped Reserves [Abstract]
Net proved developed reserves (MBOE)	1,275,447		1,015,359		840,564		877,301
Net proved undeveloped reserve (MBOE)	1,138,755		973,807		821,544		852,207
Revisions of previous estimates	97,782	[1]	113,823	[1]	(237,936)	[1]
United States [Member] | Crude Oil (MBbl) [Member]
Proved Developed and Undeveloped Reserves [Rollforward]
Net proved reserves - beginning of period	880,049	[1]	671,029	[1]	495,296	[1]
Revisions of previous estimates	28,301	[1]	57,668	[1]	4,105	[1]
Purchases in place	9,705	[1]	1,097	[1]	1,010	[1]
Extensions, discoveries and other additions	319,540	[1]	230,023	[1]	241,171	[1]
Sales in place	(4,967)	[1]	(2,337)	[1]	(15,921)	[1]
Production	(102,946)	[1]	(77,431)	[1]	(54,632)	[1]
Net proved reserves - end of period	1,129,682	[1]	880,049	[1]	671,029	[1]
Net Proved Developed and Undeveloped Reserves [Abstract]
Net proved developed reserves	493,694		382,517		281,167		213,872
Net proved undeveloped reserves	635,988		497,532		389,862		281,424
United States [Member] | Natural Gas Liquids (MBbl) [Member]
Proved Developed and Undeveloped Reserves [Rollforward]
Net proved reserves - beginning of period	376,002	[1]	318,406	[1]	226,586	[1]
Revisions of previous estimates	27,450	[1]	12,157	[1]	47,293	[1]
Purchases in place	1,812	[1]	1,202	[1]	612	[1]
Extensions, discoveries and other additions	91,683	[1]	69,187	[1]	71,396	[1]
Sales in place	(956)	[1]	(1,471)	[1]	(7,300)	[1]
Production	(29,061)	[1]	(23,479)	[1]	(20,181)	[1]
Net proved reserves - end of period	466,930	[1]	376,002	[1]	318,406	[1]
Net Proved Developed and Undeveloped Reserves [Abstract]
Net proved developed reserves	264,611		199,964		161,482		124,271
Net proved undeveloped reserves	202,319		176,038		156,924		102,315
United States [Member] | Natural Gas (MMcf) [Member]
Proved Developed and Undeveloped Reserves [Rollforward]
Net proved reserves - beginning of period	4,398,700	[2]	4,036,000	[2]	6,045,800	[2]
Revisions of previous estimates	252,200	[2]	264,000	[2]	(1,736,000)	[2]
Purchases in place	17,100	[2]	5,700	[2]	14,800	[2]
Extensions, discoveries and other additions	638,300	[2]	504,700	[2]	477,800	[2]
Sales in place	(52,400)	[2]	(69,400)	[2]	(386,200)	[2]
Production	(348,400)	[2]	(342,300)	[2]	(380,200)	[2]
Net proved reserves - end of period	4,905,500	[2]	4,398,700	[2]	4,036,000	[2]
Net Proved Developed and Undeveloped Reserves [Abstract]
Net proved developed reserves	3,102,800		2,597,300		2,387,500		3,235,000
Net proved undeveloped reserves	1,802,700		1,801,400		1,648,500		2,810,800
Canada [Member]
Proved Developed And Undeveloped Reserves (MBoe) [Rollforward]
Net proved reserves - beginning of period (MBoe)	28,339	[1]	35,804	[1]	192,448	[1]
Revisions of previous estimates	1,316	[1]	(676)	[1]	(151,015)	[1]
Purchases in place	0	[1]	0	[1]	0	[1]
Extensions, discoveries and other additions	0	[1]	693	[1]	5,860	[1]
Sales in place	(21,602)	[1]	0	[1]	(2,832)	[1]
Production	(6,080)	[1]	(7,482)	[1]	(8,657)	[1]
Net proved reserves - end of period (MBoe)	1,973	[1]	28,339	[1]	35,804	[1]
Net Proved Developed and Undeveloped Reserves [Abstract]
Net proved developed reserves (MBOE)	1,973		24,782		24,348		58,524
Net proved undeveloped reserve (MBOE)	0		3,557		11,456		133,924
Revisions of previous estimates	1,316	[1]	(676)	[1]	(151,015)	[1]
Canada [Member] | Crude Oil (MBbl) [Member]
Proved Developed and Undeveloped Reserves [Rollforward]
Net proved reserves - beginning of period	10,120	[1]	17,863	[1]	18,592	[1]
Revisions of previous estimates	(313)	[1]	(5,866)	[1]	(2,493)	[1]
Purchases in place	0	[1]	0	[1]	0	[1]
Extensions, discoveries and other additions	0	[1]	673	[1]	5,681	[1]
Sales in place	(7,656)	[1]	0	[1]	(1,343)	[1]
Production	(2,126)	[1]	(2,550)	[1]	(2,574)	[1]
Net proved reserves - end of period	25	[1]	10,120	[1]	17,863	[1]
Net Proved Developed and Undeveloped Reserves [Abstract]
Net proved developed reserves	25		6,871		6,853		8,128
Net proved undeveloped reserves	0		3,249		11,010		10,464
Canada [Member] | Natural Gas Liquids (MBbl) [Member]
Proved Developed and Undeveloped Reserves [Rollforward]
Net proved reserves - beginning of period	1,204	[1]	1,557	[1]	1,202	[1]
Revisions of previous estimates	(7)	[1]	(48)	[1]	563	[1]
Purchases in place	0	[1]	0	[1]	0	[1]
Extensions, discoveries and other additions	0	[1]	10	[1]	178	[1]
Sales in place	(823)	[1]	0	[1]	(77)	[1]
Production	(236)	[1]	(315)	[1]	(309)	[1]
Net proved reserves - end of period	138	[1]	1,204	[1]	1,557	[1]
Net Proved Developed and Undeveloped Reserves [Abstract]
Net proved developed reserves	138		896		1,111		1,092
Net proved undeveloped reserves	0		308		446		110
Canada [Member] | Natural Gas (MMcf) [Member]
Proved Developed and Undeveloped Reserves [Rollforward]
Net proved reserves - beginning of period	102,100	[2]	98,300	[2]	1,035,900	[2]
Revisions of previous estimates	9,800	[2]	31,400	[2]	(894,500)	[2]
Purchases in place	0	[2]	0	[2]	0	[2]
Extensions, discoveries and other additions	0	[2]	100	[2]	0	[2]
Sales in place	(78,700)	[2]	0	[2]	(8,500)	[2]
Production	(22,300)	[2]	(27,700)	[2]	(34,600)	[2]
Net proved reserves - end of period	10,900	[2]	102,100	[2]	98,300	[2]
Net Proved Developed and Undeveloped Reserves [Abstract]
Net proved developed reserves	10,900		102,100		98,300		295,800
Net proved undeveloped reserves	0		0		0		740,100
Trinidad [Member]
Proved Developed And Undeveloped Reserves (MBoe) [Rollforward]
Net proved reserves - beginning of period (MBoe)	88,364	[1]	101,060	[1]	128,629	[1]
Revisions of previous estimates	2,245	[1]	(3,892)	[1]	(3,953)	[1]
Purchases in place	0	[1]	0	[1]	0	[1]
Extensions, discoveries and other additions	758	[1]	13,245	[1]	0	[1]
Sales in place	0	[1]	0	[1]	0	[1]
Production	(22,430)	[1]	(22,049)	[1]	(23,616)	[1]
Net proved reserves - end of period (MBoe)	68,937	[1]	88,364	[1]	101,060	[1]
Net Proved Developed and Undeveloped Reserves [Abstract]
Net proved developed reserves (MBOE)	67,484		83,933		81,826		103,710
Net proved undeveloped reserve (MBOE)	1,453		4,431		19,234		24,919
Revisions of previous estimates	2,245	[1]	(3,892)	[1]	(3,953)	[1]
Trinidad [Member] | Crude Oil (MBbl) [Member]
Proved Developed and Undeveloped Reserves [Rollforward]
Net proved reserves - beginning of period	1,590	[1]	3,028	[1]	3,507	[1]
Revisions of previous estimates	99	[1]	(991)	[1]	71	[1]
Purchases in place	0	[1]	0	[1]	0	[1]
Extensions, discoveries and other additions	0	[1]	0	[1]	0	[1]
Sales in place	0	[1]	0	[1]	0	[1]
Production	(350)	[1]	(447)	[1]	(550)	[1]
Net proved reserves - end of period	1,339	[1]	1,590	[1]	3,028	[1]
Net Proved Developed and Undeveloped Reserves [Abstract]
Net proved developed reserves	1,339		1,505		2,377		2,657
Net proved undeveloped reserves	0		85		651		850
Trinidad [Member] | Natural Gas Liquids (MBbl) [Member]
Proved Developed and Undeveloped Reserves [Rollforward]
Net proved reserves - beginning of period	0	[1]	0	[1]	0	[1]
Revisions of previous estimates	0	[1]	0	[1]	0	[1]
Purchases in place	0	[1]	0	[1]	0	[1]
Extensions, discoveries and other additions	0	[1]	0	[1]	0	[1]
Sales in place	0	[1]	0	[1]	0	[1]
Production	0	[1]	0	[1]	0	[1]
Net proved reserves - end of period	0	[1]	0	[1]	0	[1]
Net Proved Developed and Undeveloped Reserves [Abstract]
Net proved developed reserves	0		0		0		0
Net proved undeveloped reserves	0		0		0		0
Trinidad [Member] | Natural Gas (MMcf) [Member]
Proved Developed and Undeveloped Reserves [Rollforward]
Net proved reserves - beginning of period	520,700	[2]	588,200	[2]	750,700	[2]
Revisions of previous estimates	12,900	[2]	(17,400)	[2]	(24,100)	[2]
Purchases in place	0	[2]	0	[2]	0	[2]
Extensions, discoveries and other additions	4,500	[2]	79,500	[2]	0	[2]
Sales in place	0	[2]	0	[2]	0	[2]
Production	(132,500)	[2]	(129,600)	[2]	(138,400)	[2]
Net proved reserves - end of period	405,600	[2]	520,700	[2]	588,200	[2]
Net Proved Developed and Undeveloped Reserves [Abstract]
Net proved developed reserves	396,900		494,600		476,700		606,300
Net proved undeveloped reserves	8,700		26,100		111,500		144,400
Other International [Member]
Proved Developed And Undeveloped Reserves (MBoe) [Rollforward]
Net proved reserves - beginning of period (MBoe)	12,674	[1],[3]	11,726	[1],[3]	3,178	[1],[3]
Revisions of previous estimates	(775)	[1],[3]	(265)	[1],[3]	283	[1],[3]
Purchases in place	0	[1],[3]	0	[1],[3]	0	[1],[3]
Extensions, discoveries and other additions	796	[1],[3]	1,703	[1],[3]	8,876	[1],[3]
Sales in place	0	[1],[3]	0	[1],[3]	0	[1],[3]
Production	(551)	[1],[3]	(490)	[1],[3]	(611)	[1],[3]
Net proved reserves - end of period (MBoe)	12,144	[1],[3]	12,674	[1],[3]	11,726	[1],[3]
Net Proved Developed and Undeveloped Reserves [Abstract]
Net proved developed reserves (MBOE)	3,043	[3]	3,402	[3]	3,081	[3]	3,178	[3]
Net proved undeveloped reserve (MBOE)	9,101	[3]	9,272	[3]	8,645	[3]	0	[3]
Revisions of previous estimates	(775)	[1],[3]	(265)	[1],[3]	283	[1],[3]
Other International [Member] | Crude Oil (MBbl) [Member]
Proved Developed and Undeveloped Reserves [Rollforward]
Net proved reserves - beginning of period	8,781	[1],[3]	8,898	[1],[3]	98	[1],[3]
Revisions of previous estimates	(65)	[1],[3]	(142)	[1],[3]	5	[1],[3]
Purchases in place	0	[1],[3]	0	[1],[3]	0	[1],[3]
Extensions, discoveries and other additions	14	[1],[3]	58	[1],[3]	8,834	[1],[3]
Sales in place	0	[1],[3]	0	[1],[3]	0	[1],[3]
Production	(26)	[1],[3]	(33)	[1],[3]	(39)	[1],[3]
Net proved reserves - end of period	8,704	[1],[3]	8,781	[1],[3]	8,898	[1],[3]
Net Proved Developed and Undeveloped Reserves [Abstract]
Net proved developed reserves	90	[3]	163	[3]	253	[3]	98	[3]
Net proved undeveloped reserves	8,614	[3]	8,618	[3]	8,645	[3]	0	[3]
Other International [Member] | Natural Gas Liquids (MBbl) [Member]
Proved Developed and Undeveloped Reserves [Rollforward]
Net proved reserves - beginning of period	0	[1],[3]	0	[1],[3]	0	[1],[3]
Revisions of previous estimates	0	[1],[3]	0	[1],[3]	0	[1],[3]
Purchases in place	0	[1],[3]	0	[1],[3]	0	[1],[3]
Extensions, discoveries and other additions	0	[1],[3]	0	[1],[3]	0	[1],[3]
Sales in place	0	[1],[3]	0	[1],[3]	0	[1],[3]
Production	0	[1],[3]	0	[1],[3]	0	[1],[3]
Net proved reserves - end of period	0	[1],[3]	0	[1],[3]	0	[1],[3]
Net Proved Developed and Undeveloped Reserves [Abstract]
Net proved developed reserves	0	[3]	0	[3]	0	[3]	0	[3]
Net proved undeveloped reserves	0	[3]	0	[3]	0	[3]	0	[3]
Other International [Member] | Natural Gas (MMcf) [Member]
Proved Developed and Undeveloped Reserves [Rollforward]
Net proved reserves - beginning of period	23,300	[2],[3]	17,000	[2],[3]	18,500	[2],[3]
Revisions of previous estimates	(4,300)	[2],[3]	(700)	[2],[3]	1,600	[2],[3]
Purchases in place	0	[2],[3]	0	[2],[3]	0	[2],[3]
Extensions, discoveries and other additions	4,700	[2],[3]	9,800	[2],[3]	300	[2],[3]
Sales in place	0	[2],[3]	0	[2],[3]	0	[2],[3]
Production	(3,100)	[2],[3]	(2,800)	[2],[3]	(3,400)	[2],[3]
Net proved reserves - end of period	20,600	[2],[3]	23,300	[2],[3]	17,000	[2],[3]
Net Proved Developed and Undeveloped Reserves [Abstract]
Net proved developed reserves	17,700	[3]	19,400	[3]	17,000	[3]	18,500	[3]
Net proved undeveloped reserves	2,900	[3]	3,900	[3]	0	[3]	0	[3]

[1] Thousand barrels or thousand barrels of oil equivalent, as applicable; oil equivalents include crude oil and condensate, NGL and natural gas. Oil equivalents are determined using the ratio of 1.0 barrel of crude oil and condensate or NGL to 6.0 thousand cubic feet of natural gas.

[2] Billion cubic feet.

[3] Other International includes EOG's United Kingdom, China and Argentina operations.