SUPPLEMENTAL OIL AND GAS DISCLOSURES (Unaudited) - Oil and Gas Reserve Information (Details) MBoe in Thousands, Bcf in Thousands	12 Months Ended
	Dec. 31, 2019 MBoe Bcf MMcf MBbls	Dec. 31, 2018 MBoe Bcf MMcf MBbls	Dec. 31, 2017 MBoe Bcf MMcf MBbls	Dec. 31, 2016 MBoe Bcf MMcf MBbls
Reserve Quantities [Line Items]
Proved developed reserves	892,816	1,081,316	1,023,663	1,173,635
Proved undeveloped reserves	117,972	153,081	151,323	137,616
Proved Developed and Undeveloped Reserves [Roll Forward]
Beginning balance	1,234,397	1,174,986	1,311,251
Extensions, discoveries and other additions	176,366	302,509	229,977
Purchases of minerals in-place	0	331	2,285
Revisions of previous estimates	119,473	(73,319)	10,394
Production	(172,948)	(170,051)	(166,923)
Sales of minerals in-place	(107,554)	(59)	(211,998)
Ending balance	1,010,788	1,234,397	1,174,986
United States
Reserve Quantities [Line Items]
Proved developed reserves	594,595	769,125	699,786	656,087
Proved undeveloped reserves	89,458	123,493	111,001	76,950
Proved Developed and Undeveloped Reserves [Roll Forward]
Beginning balance	892,618	810,787	733,037
Extensions, discoveries and other additions	135,174	240,322	145,322
Purchases of minerals in-place	0	331	991
Revisions of previous estimates	(133,974)	(63,451)	12,903
Production	(102,211)	(95,312)	(75,151)
Sales of minerals in-place	(107,554)	(59)	(6,315)
Ending balance	684,053	892,618	810,787
Canada
Reserve Quantities [Line Items]
Proved developed reserves	0	0	0	157,662
Proved undeveloped reserves	0	0	0	17,931
Proved Developed and Undeveloped Reserves [Roll Forward]
Beginning balance	0	0	175,593
Extensions, discoveries and other additions	0	0	24,115
Purchases of minerals in-place	0	0	1,294
Revisions of previous estimates	0	0	16,136
Production	0	0	(11,455)
Sales of minerals in-place	0	0	(205,683)
Ending balance	0	0	0
Egypt
Reserve Quantities [Line Items]
Proved developed reserves	176,470	189,871	215,364	252,630
Proved undeveloped reserves	15,038	15,045	24,112	27,336
Proved Developed and Undeveloped Reserves [Roll Forward]
Beginning balance	204,916	239,476	279,966
Extensions, discoveries and other additions	26,859	35,849	40,731
Purchases of minerals in-place	0	0	0
Revisions of previous estimates	8,355	(16,007)	(21,936)
Production	(48,622)	(54,402)	(59,285)
Sales of minerals in-place	0	0	0
Ending balance	191,508	204,916	239,476
North Sea
Reserve Quantities [Line Items]
Proved developed reserves	121,751	122,320	108,513	107,256
Proved undeveloped reserves	13,476	14,543	16,210	15,399
Proved Developed and Undeveloped Reserves [Roll Forward]
Beginning balance	136,863	124,723	122,655
Extensions, discoveries and other additions	14,333	26,338	19,809
Purchases of minerals in-place	0	0	0
Revisions of previous estimates	6,146	6,139	3,291
Production	(22,115)	(20,337)	(21,032)
Sales of minerals in-place	0	0	0
Ending balance	135,227	136,863	124,723
Crude Oil and Condensate
Reserve Quantities [Line Items]
Proved developed reserves	483,430	514,989	521,445	582,317
Proved undeveloped reserves	67,596	65,944	62,115	59,965
Proved Developed and Undeveloped Reserves [Roll Forward]
Beginning balance	580,933	583,560	642,282
Extensions, discoveries and other additions	82,353	100,131	105,579
Purchases of minerals in-place	0	140	421
Revisions of previous estimates	(6,562)	(13,277)	(675)
Production	(87,386)	(89,574)	(89,156)
Sales of minerals in-place	(18,312)	(47)	(74,891)
Ending balance	551,026	580,933	583,560
Crude Oil and Condensate | United States
Reserve Quantities [Line Items]
Proved developed reserves	278,145	300,484	304,279	300,900
Proved undeveloped reserves	46,716	45,182	31,904	21,088
Proved Developed and Undeveloped Reserves [Roll Forward]
Beginning balance	345,666	336,183	321,988
Extensions, discoveries and other additions	52,297	61,976	48,391
Purchases of minerals in-place	0	140	46
Revisions of previous estimates	(16,446)	(14,334)	825
Production	(38,344)	(38,252)	(33,394)
Sales of minerals in-place	(18,312)	(47)	(1,673)
Ending balance	324,861	345,666	336,183
Crude Oil and Condensate | Canada
Reserve Quantities [Line Items]
Proved developed reserves	0	0	0	51,508
Proved undeveloped reserves	0	0	0	7,906
Proved Developed and Undeveloped Reserves [Roll Forward]
Beginning balance	0	0	59,414
Extensions, discoveries and other additions	0	0	14,025
Purchases of minerals in-place	0	0	375
Revisions of previous estimates	0	0	1,829
Production	0	0	(2,425)
Sales of minerals in-place	0	0	(73,218)
Ending balance	0	0	0
Crude Oil and Condensate | Egypt
Reserve Quantities [Line Items]
Proved developed reserves	103,573	110,014	124,568	138,771
Proved undeveloped reserves	10,831	9,484	16,198	20,187
Proved Developed and Undeveloped Reserves [Roll Forward]
Beginning balance	119,498	140,766	158,958
Extensions, discoveries and other additions	21,039	22,473	27,140
Purchases of minerals in-place	0	0	0
Revisions of previous estimates	4,752	(9,556)	(9,839)
Production	(30,885)	(34,185)	(35,493)
Sales of minerals in-place	0	0	0
Ending balance	114,404	119,498	140,766
Crude Oil and Condensate | North Sea
Reserve Quantities [Line Items]
Proved developed reserves	101,712	104,491	92,598	91,138
Proved undeveloped reserves	10,049	11,278	14,013	10,784
Proved Developed and Undeveloped Reserves [Roll Forward]
Beginning balance	115,769	106,611	101,922
Extensions, discoveries and other additions	9,017	15,682	16,023
Purchases of minerals in-place	0	0	0
Revisions of previous estimates	5,132	10,613	6,510
Production	(18,157)	(17,137)	(17,844)
Sales of minerals in-place	0	0	0
Ending balance	111,761	115,769	106,611
Natural Gas Liquids
Reserve Quantities [Line Items]
Proved developed reserves	161,778	200,014	173,715	171,883
Proved undeveloped reserves	24,319	34,487	29,951	20,561
Proved Developed and Undeveloped Reserves [Roll Forward]
Beginning balance	234,501	203,666	192,444
Extensions, discoveries and other additions	42,067	62,578	36,495
Purchases of minerals in-place	0	40	405
Revisions of previous estimates	(31,716)	(10,038)	11,176
Production	(25,933)	(21,740)	(19,515)
Sales of minerals in-place	(32,822)	(5)	(17,339)
Ending balance	186,097	234,501	203,666
Natural Gas Liquids | United States
Reserve Quantities [Line Items]
Proved developed reserves	158,794	197,574	171,005	155,124
Proved undeveloped reserves	23,569	33,796	29,559	17,311
Proved Developed and Undeveloped Reserves [Roll Forward]
Beginning balance	231,370	200,564	172,435
Extensions, discoveries and other additions	41,343	60,990	33,806
Purchases of minerals in-place	0	40	206
Revisions of previous estimates	(32,569)	(9,250)	12,982
Production	(24,959)	(20,969)	(17,766)
Sales of minerals in-place	(32,822)	(5)	(1,099)
Ending balance	182,363	231,370	200,564
Natural Gas Liquids | Canada
Reserve Quantities [Line Items]
Proved developed reserves	0	0	0	13,866
Proved undeveloped reserves	0	0	0	2,473
Proved Developed and Undeveloped Reserves [Roll Forward]
Beginning balance	0	0	16,339
Extensions, discoveries and other additions	0	0	1,794
Purchases of minerals in-place	0	0	199
Revisions of previous estimates	0	0	(1,060)
Production	0	0	(1,032)
Sales of minerals in-place	0	0	(16,240)
Ending balance	0	0	0
Natural Gas Liquids | Egypt
Reserve Quantities [Line Items]
Proved developed reserves	667	502	685	1,266
Proved undeveloped reserves	90	60	39	131
Proved Developed and Undeveloped Reserves [Roll Forward]
Beginning balance	562	724	1,397
Extensions, discoveries and other additions	27	144	50
Purchases of minerals in-place	0	0	0
Revisions of previous estimates	508	31	(425)
Production	(340)	(337)	(298)
Sales of minerals in-place	0	0	0
Ending balance	757	562	724
Natural Gas Liquids | North Sea
Reserve Quantities [Line Items]
Proved developed reserves	2,317	1,938	2,025	1,627
Proved undeveloped reserves	660	631	353	646
Proved Developed and Undeveloped Reserves [Roll Forward]
Beginning balance	2,569	2,378	2,273
Extensions, discoveries and other additions	697	1,444	845
Purchases of minerals in-place	0	0	0
Revisions of previous estimates	345	(819)	(321)
Production	(634)	(434)	(419)
Sales of minerals in-place	0	0	0
Ending balance	2,977	2,569	2,378
Natural Gas
Reserve Quantities [Line Items]
Proved developed reserves | MMcf	1,485,649	2,197,882	1,971,018	2,516,610
Proved undeveloped reserves | MMcf	156,348	315,900	355,544	342,538
Proved Developed and Undeveloped Reserves [Roll Forward]
Beginning balance | MMcf	2,513,782	2,326,562	2,859,148
Extensions, discoveries and other additions | MMcf	311,674	838,803	527,418
Purchases of minerals in-place | MMcf	0	906	8,753
Revisions of previous estimates | MMcf	(487,168)	(300,029)	(641)
Production | MMcf	(357,771)	(352,419)	(349,509)
Sales of minerals in-place | MMcf	(338,520)	(41)	(718,607)
Ending balance | MMcf	1,641,997	2,513,782	2,326,562
Natural Gas | United States
Reserve Quantities [Line Items]
Proved developed reserves | MMcf	945,938	1,626,403	1,347,009	1,200,379
Proved undeveloped reserves | MMcf	115,040	267,090	297,226	231,304
Proved Developed and Undeveloped Reserves [Roll Forward]
Beginning balance | MMcf	1,893,493	1,644,235	1,431,683
Extensions, discoveries and other additions | MMcf	249,205	704,135	378,747
Purchases of minerals in-place | MMcf	0	906	4,434
Revisions of previous estimates | MMcf	(509,753)	(239,204)	(5,431)
Production | MMcf	(233,447)	(216,538)	(143,943)
Sales of minerals in-place | MMcf	(338,520)	(41)	(21,255)
Ending balance | MMcf	1,060,978	1,893,493	1,644,235
Natural Gas | Canada
Reserve Quantities [Line Items]
Proved developed reserves | MMcf	0	0	0	553,724
Proved undeveloped reserves | MMcf	0	0	0	45,312
Proved Developed and Undeveloped Reserves [Roll Forward]
Beginning balance | MMcf	0	0	599,036
Extensions, discoveries and other additions | MMcf	0	0	49,780
Purchases of minerals in-place	0	0	4,319
Revisions of previous estimates	0	0	92,207
Production	0	0	(47,990)
Sales of minerals in-place	0	0	(697,352)
Ending balance | MMcf	0	0	0
Natural Gas | Egypt
Reserve Quantities [Line Items]
Proved developed reserves | MMcf	433,382	476,132	540,667	675,559
Proved undeveloped reserves | MMcf	24,704	33,006	47,255	42,109
Proved Developed and Undeveloped Reserves [Roll Forward]
Beginning balance | MMcf	509,138	587,922	717,668
Extensions, discoveries and other additions | MMcf	34,758	79,394	81,245
Purchases of minerals in-place	0	0	0
Revisions of previous estimates	18,570	(38,892)	(70,030)
Production	(104,380)	(119,286)	(140,961)
Sales of minerals in-place	0	0	0
Ending balance | MMcf	458,086	509,138	587,922
Natural Gas | North Sea
Reserve Quantities [Line Items]
Proved developed reserves | MMcf	106,329	95,347	83,342	86,948
Proved undeveloped reserves | MMcf	16,604	15,804	11,063	23,813
Proved Developed and Undeveloped Reserves [Roll Forward]
Beginning balance | MMcf	111,151	94,405	110,761
Extensions, discoveries and other additions | MMcf	27,711	55,274	17,646
Purchases of minerals in-place	0	0	0
Revisions of previous estimates	4,015	(21,933)	(17,387)
Production	(19,944)	(16,595)	(16,615)
Sales of minerals in-place	0	0	0
Ending balance | MMcf	122,933	111,151	94,405
Noncontrolling Interests | Egypt
Proved Developed and Undeveloped Reserves [Roll Forward]
Proved developed reserves (Energy) | MBoe	64	68	80	93
Noncontrolling Interests | Crude Oil and Condensate | Egypt
Reserve Quantities [Line Items]
Proved developed reserves	38,000	40,000	47,000	53,000
Noncontrolling Interests | Natural Gas Liquids | Egypt
Reserve Quantities [Line Items]
Proved developed reserves	252	187	241	466
Noncontrolling Interests | Natural Gas | Egypt
Reserve Quantities [Line Items]
Proved developed reserves | Bcf	153	170	196	239