Oil and Gas Exploration and Production Industries Disclosures (Details) $ in Thousands |
12 Months Ended |
|
|
Dec. 31, 2016
USD ($)
MBoe
MMcf
MBbls
|
Dec. 31, 2015
USD ($)
MBoe
MMcf
MBbls
|
Dec. 31, 2014
MBoe
MMcf
MBbls
|
Dec. 31, 2013
MBoe
MMcf
MBbls
|
| Reserve Quantities [Line Items] |
|
|
|
|
|
| Net proved developed reserves (MBOE) | MBoe |
|
1,093,906
|
1,072,477
|
1,347,947
|
1,127,476
|
| Net Proved Undeveloped Reserves (MBOE) [Rollforward] |
|
|
|
|
|
| Balance at January 1 | MBoe |
|
1,045,640
|
1,149,309
|
991,067
|
|
| Extensions and Discoveries | MBoe |
|
138,101
|
205,152
|
403,713
|
|
| Revisions | MBoe |
|
64,413
|
(241,973)
|
(79,630)
|
|
| Acquisition of Reserves | MBoe |
|
0
|
54,458
|
4,239
|
|
| Sales of Reserves | MBoe |
|
(45,917)
|
0
|
(10,176)
|
|
| Conversion to Proved Developed Reserves | MBoe |
|
(149,210)
|
(121,306)
|
(159,904)
|
|
| Balance at December 31 | MBoe |
|
1,053,027
|
1,045,640
|
1,149,309
|
|
| Capitalized Costs, Oil and Gas Producing Activities, Gross [Abstract] |
|
|
|
|
|
| Proved properties | $ |
|
$ 45,751,965
|
$ 49,623,518
|
|
|
| Unproved properties | $ |
|
3,840,126
|
989,723
|
|
|
| Total | $ |
|
49,592,091
|
50,613,241
|
|
|
| Accumulated depreciation, depletion and amortization | $ |
|
(26,247,062)
|
(28,877,593)
|
|
|
| Net capitalized costs | $ |
|
$ 23,345,029
|
$ 21,735,648
|
|
|
| Crude Oil (MBbl) |
|
|
|
|
|
| Reserve Quantities [Line Items] |
|
|
|
|
|
| Net proved developed reserves |
|
516,625
|
445,202
|
495,148
|
391,056
|
| Net proved undeveloped reserves |
|
660,960
|
652,394
|
644,602
|
509,484
|
| Proved Developed Reserves [Rollforward] |
|
|
|
|
|
| Net proved reserves - beginning of period |
[1] |
1,097,596
|
1,139,750
|
900,540
|
|
| Revisions of previous estimates |
[1] |
42,955
|
(114,925)
|
28,022
|
|
| Purchases in place |
[1] |
25,795
|
35,922
|
9,705
|
|
| Extensions, discoveries and other additions |
[1] |
123,441
|
141,386
|
319,554
|
|
| Sales in place |
[1] |
(8,791)
|
(740)
|
(12,623)
|
|
| Production |
[1] |
(103,411)
|
(103,797)
|
(105,448)
|
|
| Net proved reserves - end of period |
[1] |
1,177,585
|
1,097,596
|
1,139,750
|
|
| Natural Gas Liquids (MBbl) |
|
|
|
|
|
| Reserve Quantities [Line Items] |
|
|
|
|
|
| Net proved developed reserves |
|
230,219
|
205,898
|
264,749
|
200,860
|
| Net proved undeveloped reserves |
|
186,147
|
176,977
|
202,319
|
176,346
|
| Proved Developed Reserves [Rollforward] |
|
|
|
|
|
| Net proved reserves - beginning of period |
[1] |
382,875
|
467,068
|
377,206
|
|
| Revisions of previous estimates |
[1] |
53,771
|
(113,222)
|
27,443
|
|
| Purchases in place |
[1] |
1,284
|
8,251
|
1,812
|
|
| Extensions, discoveries and other additions |
[1] |
41,862
|
49,147
|
91,683
|
|
| Sales in place |
[1] |
(33,548)
|
(271)
|
(1,779)
|
|
| Production |
[1] |
(29,878)
|
(28,098)
|
(29,297)
|
|
| Net proved reserves - end of period |
[1] |
416,366
|
382,875
|
467,068
|
|
| Natural Gas (MMcf) |
|
|
|
|
|
| Reserve Quantities [Line Items] |
|
|
|
|
|
| Net proved developed reserves | MMcf |
|
2,082,400
|
2,528,300
|
3,528,300
|
3,213,400
|
| Net proved undeveloped reserves | MMcf |
|
1,235,500
|
1,297,600
|
1,814,300
|
1,831,400
|
| Proved Developed Reserves [Rollforward] |
|
|
|
|
|
| Net proved reserves - beginning of period | MMcf |
[2] |
3,825,900
|
5,342,600
|
5,044,800
|
|
| Revisions of previous estimates | MMcf |
[2] |
333,100
|
(1,430,700)
|
270,600
|
|
| Purchases in place | MMcf |
[2] |
91,500
|
72,300
|
17,100
|
|
| Extensions, discoveries and other additions | MMcf |
[2] |
262,000
|
332,400
|
647,500
|
|
| Sales in place | MMcf |
[2] |
(752,000)
|
(15,000)
|
(131,100)
|
|
| Production | MMcf |
[2] |
(442,600)
|
(475,700)
|
(506,300)
|
|
| Net proved reserves - end of period | MMcf |
[2] |
3,317,900
|
3,825,900
|
5,342,600
|
|
| Oil Equivalents (MBoe) |
|
|
|
|
|
| Reserve Quantities [Line Items] |
|
|
|
|
|
| Net proved undeveloped reserve (MBOE) | MBoe |
|
1,053,027
|
1,045,640
|
1,149,309
|
991,067
|
| Proved Developed Reserves (MBoe) [Roll Forward] |
|
|
|
|
|
| Net proved reserves - beginning of period | MBoe |
[1] |
2,118,117
|
2,497,256
|
2,118,543
|
|
| Revisions of previous estimates | MBoe |
[1] |
152,242
|
(466,604)
|
100,568
|
|
| Purchases in place | MBoe |
[1] |
42,330
|
56,215
|
14,367
|
|
| Extensions, discoveries and other additions | MBoe |
[1] |
208,963
|
245,931
|
519,167
|
|
| Sales in place | MBoe |
[1] |
(167,669)
|
(3,506)
|
(36,263)
|
|
| Production | MBoe |
[1] |
(207,050)
|
(211,175)
|
(219,126)
|
|
| Net proved reserves - end of period | MBoe |
[1] |
2,146,933
|
2,118,117
|
2,497,256
|
|
| United States |
|
|
|
|
|
| Reserve Quantities [Line Items] |
|
|
|
|
|
| Net proved developed reserves (MBOE) | MBoe |
|
1,038,483
|
1,018,491
|
1,275,447
|
1,015,359
|
| United States | Crude Oil (MBbl) |
|
|
|
|
|
| Reserve Quantities [Line Items] |
|
|
|
|
|
| Net proved developed reserves |
|
507,531
|
444,070
|
493,694
|
382,517
|
| Net proved undeveloped reserves |
|
660,960
|
643,790
|
635,988
|
497,532
|
| Proved Developed Reserves [Rollforward] |
|
|
|
|
|
| Net proved reserves - beginning of period |
[1] |
1,087,860
|
1,129,682
|
880,049
|
|
| Revisions of previous estimates |
[1] |
42,040
|
(114,924)
|
28,301
|
|
| Purchases in place |
[1] |
25,795
|
35,922
|
9,705
|
|
| Extensions, discoveries and other additions |
[1] |
123,441
|
141,310
|
319,540
|
|
| Sales in place |
[1] |
(8,791)
|
(730)
|
(4,967)
|
|
| Production |
[1] |
(101,854)
|
(103,400)
|
(102,946)
|
|
| Net proved reserves - end of period |
[1] |
1,168,491
|
1,087,860
|
1,129,682
|
|
| United States | Natural Gas Liquids (MBbl) |
|
|
|
|
|
| Reserve Quantities [Line Items] |
|
|
|
|
|
| Net proved developed reserves |
|
230,219
|
205,898
|
264,611
|
199,964
|
| Net proved undeveloped reserves |
|
186,147
|
176,977
|
202,319
|
176,038
|
| Proved Developed Reserves [Rollforward] |
|
|
|
|
|
| Net proved reserves - beginning of period |
[1] |
382,875
|
466,930
|
376,002
|
|
| Revisions of previous estimates |
[1] |
53,771
|
(113,290)
|
27,450
|
|
| Purchases in place |
[1] |
1,284
|
8,251
|
1,812
|
|
| Extensions, discoveries and other additions |
[1] |
41,862
|
49,147
|
91,683
|
|
| Sales in place |
[1] |
(33,548)
|
(84)
|
(956)
|
|
| Production |
[1] |
(29,878)
|
(28,079)
|
(29,061)
|
|
| Net proved reserves - end of period |
[1] |
416,366
|
382,875
|
466,930
|
|
| United States | Natural Gas (MMcf) |
|
|
|
|
|
| Reserve Quantities [Line Items] |
|
|
|
|
|
| Net proved developed reserves | MMcf |
|
1,804,400
|
2,211,200
|
3,102,800
|
2,597,300
|
| Net proved undeveloped reserves | MMcf |
|
1,216,800
|
1,278,600
|
1,802,700
|
1,801,400
|
| Proved Developed Reserves [Rollforward] |
|
|
|
|
|
| Net proved reserves - beginning of period | MMcf |
[2] |
3,489,800
|
4,905,500
|
4,398,700
|
|
| Revisions of previous estimates | MMcf |
[2] |
298,400
|
(1,453,100)
|
252,200
|
|
| Purchases in place | MMcf |
[2] |
91,500
|
72,300
|
17,100
|
|
| Extensions, discoveries and other additions | MMcf |
[2] |
202,100
|
306,300
|
638,300
|
|
| Sales in place | MMcf |
[2] |
(752,000)
|
(3,900)
|
(52,400)
|
|
| Production | MMcf |
[2] |
(308,600)
|
(337,300)
|
(348,400)
|
|
| Net proved reserves - end of period | MMcf |
[2] |
3,021,200
|
3,489,800
|
4,905,500
|
|
| United States | Oil Equivalents (MBoe) |
|
|
|
|
|
| Reserve Quantities [Line Items] |
|
|
|
|
|
| Net proved undeveloped reserve (MBOE) | MBoe |
|
1,049,909
|
1,033,870
|
1,138,755
|
973,807
|
| Proved Developed Reserves (MBoe) [Roll Forward] |
|
|
|
|
|
| Net proved reserves - beginning of period | MBoe |
[1] |
2,052,361
|
2,414,202
|
1,989,166
|
|
| Revisions of previous estimates | MBoe |
[1] |
145,542
|
(470,401)
|
97,782
|
|
| Purchases in place | MBoe |
[1] |
42,330
|
56,215
|
14,367
|
|
| Extensions, discoveries and other additions | MBoe |
[1] |
198,973
|
241,513
|
517,613
|
|
| Sales in place | MBoe |
[1] |
(167,669)
|
(1,467)
|
(14,661)
|
|
| Production | MBoe |
[1] |
(183,145)
|
(187,701)
|
(190,065)
|
|
| Net proved reserves - end of period | MBoe |
[1] |
2,088,392
|
2,052,361
|
2,414,202
|
|
| Trinidad |
|
|
|
|
|
| Reserve Quantities [Line Items] |
|
|
|
|
|
| Net proved developed reserves (MBOE) | MBoe |
|
44,543
|
50,677
|
67,484
|
83,933
|
| Trinidad | Crude Oil (MBbl) |
|
|
|
|
|
| Reserve Quantities [Line Items] |
|
|
|
|
|
| Net proved developed reserves |
|
839
|
1,069
|
1,339
|
1,505
|
| Net proved undeveloped reserves |
|
0
|
0
|
0
|
85
|
| Proved Developed Reserves [Rollforward] |
|
|
|
|
|
| Net proved reserves - beginning of period |
[1] |
1,069
|
1,339
|
1,590
|
|
| Revisions of previous estimates |
[1] |
54
|
(1)
|
99
|
|
| Purchases in place |
[1] |
0
|
0
|
0
|
|
| Extensions, discoveries and other additions |
[1] |
0
|
63
|
0
|
|
| Sales in place |
[1] |
0
|
0
|
0
|
|
| Production |
[1] |
(284)
|
(332)
|
(350)
|
|
| Net proved reserves - end of period |
[1] |
839
|
1,069
|
1,339
|
|
| Trinidad | Natural Gas Liquids (MBbl) |
|
|
|
|
|
| Reserve Quantities [Line Items] |
|
|
|
|
|
| Net proved developed reserves |
|
0
|
0
|
0
|
0
|
| Net proved undeveloped reserves |
|
0
|
0
|
0
|
0
|
| Proved Developed Reserves [Rollforward] |
|
|
|
|
|
| Net proved reserves - beginning of period |
[1] |
0
|
0
|
0
|
|
| Revisions of previous estimates |
[1] |
0
|
0
|
0
|
|
| Purchases in place |
[1] |
0
|
0
|
0
|
|
| Extensions, discoveries and other additions |
[1] |
0
|
0
|
0
|
|
| Sales in place |
[1] |
0
|
0
|
0
|
|
| Production |
[1] |
0
|
0
|
0
|
|
| Net proved reserves - end of period |
[1] |
0
|
0
|
0
|
|
| Trinidad | Natural Gas (MMcf) |
|
|
|
|
|
| Reserve Quantities [Line Items] |
|
|
|
|
|
| Net proved developed reserves | MMcf |
|
262,200
|
297,600
|
396,900
|
494,600
|
| Net proved undeveloped reserves | MMcf |
|
18,700
|
19,000
|
8,700
|
26,100
|
| Proved Developed Reserves [Rollforward] |
|
|
|
|
|
| Net proved reserves - beginning of period | MMcf |
[2] |
316,600
|
405,600
|
520,700
|
|
| Revisions of previous estimates | MMcf |
[2] |
29,500
|
16,800
|
12,900
|
|
| Purchases in place | MMcf |
[2] |
0
|
0
|
0
|
|
| Extensions, discoveries and other additions | MMcf |
[2] |
59,900
|
21,700
|
4,500
|
|
| Sales in place | MMcf |
[2] |
0
|
0
|
0
|
|
| Production | MMcf |
[2] |
(125,100)
|
(127,500)
|
(132,500)
|
|
| Net proved reserves - end of period | MMcf |
[2] |
280,900
|
316,600
|
405,600
|
|
| Trinidad | Oil Equivalents (MBoe) |
|
|
|
|
|
| Reserve Quantities [Line Items] |
|
|
|
|
|
| Net proved undeveloped reserve (MBOE) | MBoe |
|
3,118
|
3,166
|
1,453
|
4,431
|
| Proved Developed Reserves (MBoe) [Roll Forward] |
|
|
|
|
|
| Net proved reserves - beginning of period | MBoe |
[1] |
53,843
|
68,937
|
88,364
|
|
| Revisions of previous estimates | MBoe |
[1] |
4,978
|
2,802
|
2,245
|
|
| Purchases in place | MBoe |
[1] |
0
|
0
|
0
|
|
| Extensions, discoveries and other additions | MBoe |
[1] |
9,990
|
3,682
|
758
|
|
| Sales in place | MBoe |
[1] |
0
|
0
|
0
|
|
| Production | MBoe |
[1] |
(21,150)
|
(21,578)
|
(22,430)
|
|
| Net proved reserves - end of period | MBoe |
[1] |
47,661
|
53,843
|
68,937
|
|
| Other International |
|
|
|
|
|
| Reserve Quantities [Line Items] |
|
|
|
|
|
| Net proved developed reserves (MBOE) | MBoe |
[3] |
10,880
|
3,309
|
5,016
|
28,184
|
| Other International | Crude Oil (MBbl) |
|
|
|
|
|
| Reserve Quantities [Line Items] |
|
|
|
|
|
| Net proved developed reserves |
[3] |
8,255
|
63
|
115
|
7,034
|
| Net proved undeveloped reserves |
[3] |
0
|
8,604
|
8,614
|
11,867
|
| Proved Developed Reserves [Rollforward] |
|
|
|
|
|
| Net proved reserves - beginning of period |
[1],[3] |
8,667
|
8,729
|
18,901
|
|
| Revisions of previous estimates |
[1],[3] |
861
|
0
|
(378)
|
|
| Purchases in place |
[1],[3] |
0
|
0
|
0
|
|
| Extensions, discoveries and other additions |
[1],[3] |
0
|
13
|
14
|
|
| Sales in place |
[1],[3] |
0
|
(10)
|
(7,656)
|
|
| Production |
[1],[3] |
(1,273)
|
(65)
|
(2,152)
|
|
| Net proved reserves - end of period |
[1],[3] |
8,255
|
8,667
|
8,729
|
|
| Other International | Natural Gas Liquids (MBbl) |
|
|
|
|
|
| Reserve Quantities [Line Items] |
|
|
|
|
|
| Net proved developed reserves |
[3] |
0
|
0
|
138
|
896
|
| Net proved undeveloped reserves |
[3] |
0
|
0
|
0
|
308
|
| Proved Developed Reserves [Rollforward] |
|
|
|
|
|
| Net proved reserves - beginning of period |
[1],[3] |
0
|
138
|
1,204
|
|
| Revisions of previous estimates |
[1],[3] |
0
|
68
|
(7)
|
|
| Purchases in place |
[1],[3] |
0
|
0
|
0
|
|
| Extensions, discoveries and other additions |
[1],[3] |
0
|
0
|
0
|
|
| Sales in place |
[1],[3] |
0
|
(187)
|
(823)
|
|
| Production |
[1],[3] |
0
|
(19)
|
(236)
|
|
| Net proved reserves - end of period |
[1],[3] |
0
|
0
|
138
|
|
| Other International | Natural Gas (MMcf) |
|
|
|
|
|
| Reserve Quantities [Line Items] |
|
|
|
|
|
| Net proved developed reserves | MMcf |
[3] |
15,800
|
19,500
|
28,600
|
121,500
|
| Net proved undeveloped reserves | MMcf |
[3] |
0
|
0
|
2,900
|
3,900
|
| Proved Developed Reserves [Rollforward] |
|
|
|
|
|
| Net proved reserves - beginning of period | MMcf |
[2],[3] |
19,500
|
31,500
|
125,400
|
|
| Revisions of previous estimates | MMcf |
[2],[3] |
5,200
|
5,600
|
5,500
|
|
| Purchases in place | MMcf |
[2],[3] |
0
|
0
|
0
|
|
| Extensions, discoveries and other additions | MMcf |
[2],[3] |
0
|
4,400
|
4,700
|
|
| Sales in place | MMcf |
[2],[3] |
0
|
(11,100)
|
(78,700)
|
|
| Production | MMcf |
[2],[3] |
(8,900)
|
(10,900)
|
(25,400)
|
|
| Net proved reserves - end of period | MMcf |
[2],[3] |
15,800
|
19,500
|
31,500
|
|
| Other International | Oil Equivalents (MBoe) |
|
|
|
|
|
| Reserve Quantities [Line Items] |
|
|
|
|
|
| Net proved undeveloped reserve (MBOE) | MBoe |
[3] |
0
|
8,604
|
9,101
|
12,829
|
| Proved Developed Reserves (MBoe) [Roll Forward] |
|
|
|
|
|
| Net proved reserves - beginning of period | MBoe |
[1],[3] |
11,913
|
14,117
|
41,013
|
|
| Revisions of previous estimates | MBoe |
[1],[3] |
1,722
|
995
|
541
|
|
| Purchases in place | MBoe |
[1],[3] |
0
|
0
|
0
|
|
| Extensions, discoveries and other additions | MBoe |
[1],[3] |
0
|
736
|
796
|
|
| Sales in place | MBoe |
[1],[3] |
0
|
(2,039)
|
(21,602)
|
|
| Production | MBoe |
[1],[3] |
(2,755)
|
(1,896)
|
(6,631)
|
|
| Net proved reserves - end of period | MBoe |
[1],[3] |
10,880
|
11,913
|
14,117
|
|
|
|