SUPPLEMENTAL OIL AND GAS DISCLOSURES (Unaudited) - Oil and Gas Reserve Information (Details) MBoe in Thousands	12 Months Ended
	Dec. 31, 2020 MBoe MBbls MMcf	Dec. 31, 2019 MBoe MBbls MMcf	Dec. 31, 2018 MBoe MMcf MBbls	Dec. 31, 2017 MBoe MMcf MBbls
Reserve Quantities [Line Items]
Proved developed reserves	797,843	892,816	1,081,316	1,023,663
Proved undeveloped reserves	75,840	117,972	153,081	151,323
Proved Developed and Undeveloped Reserves [Roll Forward]
Beginning balance	1,010,788	1,234,397	1,174,986
Extensions, discoveries and other additions	78,303	176,366	302,509
Purchases of minerals in-place			331
Revisions of previous estimates	(44,910)	(119,473)	(73,319)
Production	(160,945)	(172,948)	(170,051)
Sales of minerals in-place	(9,553)	(107,554)	(59)
Ending balance	873,683	1,010,788	1,234,397
United States
Reserve Quantities [Line Items]
Proved developed reserves	532,994	594,595	769,125	699,786
Proved undeveloped reserves	53,408	89,458	123,493	111,001
Proved Developed and Undeveloped Reserves [Roll Forward]
Beginning balance	684,053	892,618	810,787
Extensions, discoveries and other additions	39,454	135,174	240,322
Purchases of minerals in-place			331
Revisions of previous estimates	(33,854)	(133,974)	(63,451)
Production	(93,698)	(102,211)	(95,312)
Sales of minerals in-place	(9,553)	(107,554)	(59)
Ending balance	586,402	684,053	892,618
Egypt
Reserve Quantities [Line Items]
Proved developed reserves	164,870	176,470	189,871	215,364
Proved undeveloped reserves	13,449	15,038	15,045	24,112
Proved Developed and Undeveloped Reserves [Roll Forward]
Beginning balance	191,508	204,916	239,476
Extensions, discoveries and other additions	31,905	26,859	35,849
Purchases of minerals in-place			0
Revisions of previous estimates	(502)	8,355	(16,007)
Production	(44,592)	(48,622)	(54,402)
Sales of minerals in-place	0	0	0
Ending balance	178,319	191,508	204,916
North Sea
Reserve Quantities [Line Items]
Proved developed reserves	99,979	121,751	122,320	108,513
Proved undeveloped reserves	8,983	13,476	14,543	16,210
Proved Developed and Undeveloped Reserves [Roll Forward]
Beginning balance	135,227	136,863	124,723
Extensions, discoveries and other additions	6,944	14,333	26,338
Purchases of minerals in-place			0
Revisions of previous estimates	(10,554)	6,146	6,139
Production	(22,655)	(22,115)	(20,337)
Sales of minerals in-place	0	0	0
Ending balance	108,962	135,227	136,863
Noncontrolling Interests | Egypt
Proved Developed and Undeveloped Reserves [Roll Forward]
Proved developed reserves (Energy) | MBoe	59	64	68	80
Crude Oil and Condensate
Reserve Quantities [Line Items]
Proved developed reserves	389,483	483,430	514,989	521,445
Proved undeveloped reserves	44,017	67,596	65,944	62,115
Proved Developed and Undeveloped Reserves [Roll Forward]
Beginning balance	551,026	580,933	583,560
Extensions, discoveries and other additions	40,988	82,353	100,131
Purchases of minerals in-place			140
Revisions of previous estimates	(71,462)	(6,562)	(13,277)
Production	(78,331)	(87,386)	(89,574)
Sales of minerals in-place	(8,721)	(18,312)	(47)
Ending balance	433,500	551,026	580,933
Crude Oil and Condensate | United States
Reserve Quantities [Line Items]
Proved developed reserves	206,936	278,145	300,484	304,279
Proved undeveloped reserves	25,516	46,716	45,182	31,904
Proved Developed and Undeveloped Reserves [Roll Forward]
Beginning balance	324,861	345,666	336,183
Extensions, discoveries and other additions	17,858	52,297	61,976
Purchases of minerals in-place			140
Revisions of previous estimates	(69,247)	(16,446)	(14,334)
Production	(32,299)	(38,344)	(38,252)
Sales of minerals in-place	(8,721)	(18,312)	(47)
Ending balance	232,452	324,861	345,666
Crude Oil and Condensate | Egypt
Reserve Quantities [Line Items]
Proved developed reserves	95,981	103,573	110,014	124,568
Proved undeveloped reserves	11,228	10,831	9,484	16,198
Proved Developed and Undeveloped Reserves [Roll Forward]
Beginning balance	114,404	119,498	140,766
Extensions, discoveries and other additions	17,855	21,039	22,473
Purchases of minerals in-place			0
Revisions of previous estimates	2,541	4,752	(9,556)
Production	(27,591)	(30,885)	(34,185)
Sales of minerals in-place	0	0	0
Ending balance	107,209	114,404	119,498
Crude Oil and Condensate | North Sea
Reserve Quantities [Line Items]
Proved developed reserves	86,566	101,712	104,491	92,598
Proved undeveloped reserves	7,273	10,049	11,278	14,013
Proved Developed and Undeveloped Reserves [Roll Forward]
Beginning balance	111,761	115,769	106,611
Extensions, discoveries and other additions	5,275	9,017	15,682
Purchases of minerals in-place			0
Revisions of previous estimates	(4,756)	5,132	10,613
Production	(18,441)	(18,157)	(17,137)
Sales of minerals in-place	0	0	0
Ending balance	93,839	111,761	115,769
Crude Oil and Condensate | Noncontrolling Interests | Egypt
Reserve Quantities [Line Items]
Proved developed reserves	36,000	38,000	40,000	47,000
Natural Gas Liquids
Reserve Quantities [Line Items]
Proved developed reserves	153,368	161,778	200,014	173,715
Proved undeveloped reserves	15,587	24,319	34,487	29,951
Proved Developed and Undeveloped Reserves [Roll Forward]
Beginning balance	186,097	234,501	203,666
Extensions, discoveries and other additions	11,844	42,067	62,578
Purchases of minerals in-place			40
Revisions of previous estimates	(412)	(31,716)	(10,038)
Production	(28,118)	(25,933)	(21,740)
Sales of minerals in-place	(456)	(32,822)	(5)
Ending balance	168,955	186,097	234,501
Natural Gas Liquids | United States
Reserve Quantities [Line Items]
Proved developed reserves	150,599	158,794	197,574	171,005
Proved undeveloped reserves	15,141	23,569	33,796	29,559
Proved Developed and Undeveloped Reserves [Roll Forward]
Beginning balance	182,363	231,370	200,564
Extensions, discoveries and other additions	11,435	41,343	60,990
Purchases of minerals in-place			40
Revisions of previous estimates	(469)	(32,569)	(9,250)
Production	(27,133)	(24,959)	(20,969)
Sales of minerals in-place	(456)	(32,822)	(5)
Ending balance	165,740	182,363	231,370
Natural Gas Liquids | Egypt
Reserve Quantities [Line Items]
Proved developed reserves	716	667	502	685
Proved undeveloped reserves	126	90	60	39
Proved Developed and Undeveloped Reserves [Roll Forward]
Beginning balance	757	562	724
Extensions, discoveries and other additions	97	27	144
Purchases of minerals in-place			0
Revisions of previous estimates	264	508	31
Production	(276)	(340)	(337)
Sales of minerals in-place	0	0	0
Ending balance	842	757	562
Natural Gas Liquids | North Sea
Reserve Quantities [Line Items]
Proved developed reserves	2,053	2,317	1,938	2,025
Proved undeveloped reserves	320	660	631	353
Proved Developed and Undeveloped Reserves [Roll Forward]
Beginning balance	2,977	2,569	2,378
Extensions, discoveries and other additions	312	697	1,444
Purchases of minerals in-place			0
Revisions of previous estimates	(207)	345	(819)
Production	(709)	(634)	(434)
Sales of minerals in-place	0	0	0
Ending balance	2,373	2,977	2,569
Natural Gas Liquids | Noncontrolling Interests | Egypt
Reserve Quantities [Line Items]
Proved developed reserves	281	252	187	241
Natural Gas
Reserve Quantities [Line Items]
Proved developed reserves | MMcf	1,529,950	1,485,649	2,197,882	1,971,018
Proved undeveloped reserves | MMcf	97,417	156,348	315,900	355,544
Proved Developed and Undeveloped Reserves [Roll Forward]
Beginning balance | MMcf	1,641,997	2,513,782	2,326,562
Extensions, discoveries and other additions | MMcf	152,823	311,674	838,803
Purchases of minerals in-place | MMcf			906
Revisions of previous estimates | MMcf	161,776	(487,168)	(300,029)
Production | MMcf	(326,974)	(357,771)	(352,419)
Sales of minerals in-place | MMcf	(2,255)	(338,520)	(41)
Ending balance | MMcf	1,627,367	1,641,997	2,513,782
Natural Gas | United States
Reserve Quantities [Line Items]
Proved developed reserves | MMcf	1,052,756	945,938	1,626,403	1,347,009
Proved undeveloped reserves | MMcf	76,504	115,040	267,090	297,226
Proved Developed and Undeveloped Reserves [Roll Forward]
Beginning balance | MMcf	1,060,978	1,893,493	1,644,235
Extensions, discoveries and other additions | MMcf	60,965	249,205	704,135
Purchases of minerals in-place | MMcf			906
Revisions of previous estimates | MMcf	215,166	(509,753)	(239,204)
Production | MMcf	(205,594)	(233,447)	(216,538)
Sales of minerals in-place | MMcf	(2,255)	(338,520)	(41)
Ending balance | MMcf	1,129,260	1,060,978	1,893,493
Natural Gas | Egypt
Reserve Quantities [Line Items]
Proved developed reserves | MMcf	409,035	433,382	476,132	540,667
Proved undeveloped reserves | MMcf	12,572	24,704	33,006	47,255
Proved Developed and Undeveloped Reserves [Roll Forward]
Beginning balance | MMcf	458,086	509,138	587,922
Extensions, discoveries and other additions | MMcf	83,718	34,758	79,394
Purchases of minerals in-place			0
Revisions of previous estimates	(19,849)	18,570	(38,892)
Production	(100,348)	(104,380)	(119,286)
Sales of minerals in-place	0	0	0
Ending balance | MMcf	421,607	458,086	509,138
Natural Gas | North Sea
Reserve Quantities [Line Items]
Proved developed reserves | MMcf	68,159	106,329	95,347	83,342
Proved undeveloped reserves | MMcf	8,341	16,604	15,804	11,063
Proved Developed and Undeveloped Reserves [Roll Forward]
Beginning balance | MMcf	122,933	111,151	94,405
Extensions, discoveries and other additions | MMcf	8,140	27,711	55,274
Purchases of minerals in-place			0
Revisions of previous estimates	(33,541)	4,015	(21,933)
Production	(21,032)	(19,944)	(16,595)
Sales of minerals in-place	0	0	0
Ending balance | MMcf	76,500	122,933	111,151
Natural Gas | Noncontrolling Interests | Egypt
Reserve Quantities [Line Items]
Proved developed reserves | MMcf	141,000	153,000	170,000	196,000