INDUSTRY SEGMENTS AND GEOGRAPHIC AREAS - RESULTS OF OPERATIONS (Details) $ in Millions	3 Months Ended		12 Months Ended
	Jun. 30, 2020 USD ($)	Mar. 31, 2020 USD ($)	Dec. 31, 2020 USD ($) segment	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)
Segment Reporting [Abstract]
Number of operating segments | segment			3
Segment Information
Net sales			$ 17,809	$ 20,911	$ 17,824
Income (loss) from continuing operations before income taxes			(15,705)	354	5,608
Income tax expense			2,172	(861)	(1,477)
Income (loss) from continuing operations			(13,533)	(507)	4,131
INVESTMENTS IN UNCONSOLIDATED ENTITIES			3,250	6,389	1,680
Property, plant and equipment additions			2,619	6,453	5,020
Depreciation, depletion and amortization			8,097	6,140	3,977
Total assets			80,064	107,190	42,159
Pre-tax impairment and related charges on domestic undeveloped leases				285
Impairments of assets	$ 8,600			285
Employee severance and related costs				1,000
Crucial seismic data				401
Bank, legal and consulting fees				213
Tax expense (benefit) of pre-tax adjustments			(1,900)	(245)	198
Gains (losses) on interest rate swaps and warrants, net			(423)	233	0
Goodwill derecognized		$ 1,200
Anadarko Acquisition-related costs			339	1,647	0
Qatar ISND and ISSD
Segment Information
Impairments of assets					416
Oil and gas
Segment Information
Impairments of assets	$ 6,400	$ 581
Midstream and marketing
Segment Information
Impairments of assets					100
Midstream and marketing | Non Core Midstream Assets
Segment Information
Pre-tax net gain from divestiture					907
Operating segments | Oil and gas
Segment Information
Net sales			13,066	13,941	10,441
Income (loss) from continuing operations before income taxes			(9,632)	2,520	2,442
Income tax expense			0	0	0
Income (loss) from continuing operations			(9,632)	2,520	2,442
INVESTMENTS IN UNCONSOLIDATED ENTITIES			168	181	0
Property, plant and equipment additions			2,279	5,571	4,443
Depreciation, depletion and amortization			7,414	5,153	3,254
Total assets			62,931	80,093	24,874
Gain on sale				475
Pre-tax impairment and related charges on domestic undeveloped leases				39
Impairments of assets			7,100
Impairment charges				285
Pre-tax loss on sale of properties			1,600
Gains (losses) on interest rate swaps and warrants, net			1,100
Operating segments | Chemical
Segment Information
Net sales			3,733	4,102	4,657
Income (loss) from continuing operations before income taxes			664	799	1,159
Income tax expense			0	0	0
Income (loss) from continuing operations			664	799	1,159
INVESTMENTS IN UNCONSOLIDATED ENTITIES			645	689	733
Property, plant and equipment additions			261	272	277
Depreciation, depletion and amortization			356	368	354
Total assets			4,326	4,361	4,359
Operating segments | Midstream and marketing
Segment Information
Net sales			1,768	4,132	3,656
Income (loss) from continuing operations before income taxes			(4,175)	241	2,802
Income tax expense			0	0	0
Income (loss) from continuing operations			(4,175)	241	2,802
INVESTMENTS IN UNCONSOLIDATED ENTITIES			2,437	5,519	947
Property, plant and equipment additions			50	475	221
Depreciation, depletion and amortization			312	563	331
Total assets			9,856	14,915	9,392
Charge upon loss of control				1,000
Pre-tax gain on sale of equity investment				114
Impairment of equity method investment			2,700
Equity method investment, loss from goodwill impairment			236
Goodwill derecognized			1,400
Operating segments | Midstream and marketing | Interest Rate Swaps
Segment Information
Mark to market gain on interest rate swap				30
Corporate and eliminations
Segment Information
Net sales			(758)	(1,264)	(930)
Income (loss) from continuing operations before income taxes			(2,562)	(3,206)	(795)
Income tax expense			2,172	(861)	(1,477)
Income (loss) from continuing operations			(390)	(4,067)	(2,272)
INVESTMENTS IN UNCONSOLIDATED ENTITIES			0	0	0
Property, plant and equipment additions			29	135	79
Depreciation, depletion and amortization			15	56	38
Total assets			2,951	$ 7,821	$ 3,534
Anadarko Acquisition-related costs			339
Loss on interest rate swaps			$ 428