INVESTMENTS AND RELATED-PARTY TRANSACTIONS (Details) - USD ($) shares in Millions, $ in Millions		1 Months Ended				3 Months Ended		9 Months Ended	12 Months Ended
		Dec. 31, 2021	Nov. 30, 2021	Mar. 31, 2021	Sep. 30, 2019	Sep. 30, 2020	Mar. 31, 2020	Sep. 30, 2020	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Equity Method Investments
Equity method investment amounts		$ 2,938							$ 2,938	$ 3,250
Dividends received as return on investment									652	678	$ 422
Cumulative undistributed earnings		242							242	166
Excess of investments in equity investees over the underlying equity in net assets		667							667
Excess of investments in equity investees over the underlying equity in net assets, which represents goodwill		347							347
Equity-method investments financial information summarized by Income Statement line item
Revenues and other income									26,314	16,261	21,750
Costs and expenses									23,362	31,913	22,002
Net income									2,952	(15,652)	(252)
Equity-method investments financial information summarized by Balance Sheet line item
Current assets		10,211							10,211	8,819
Current liabilities		8,324							8,324	8,223
Long-term debt	[1]	29,431							29,431	35,745
Other non-current liabilities		16,954							16,954	17,523
Stockholders’ equity		20,327							20,327	18,573
RELATED-PARTY TRANSACTIONS
Sales									261	301	691
Purchases									773	1,112	463
Services									942	1,101	28
Advances and amounts due from related parties (c)		57							57	62	133
Amounts due to related parties		$ 280							$ 280	296	463
Disposal Group, Disposed of by Sale, Not Discontinued Operations | WES
Equity Method Investments
Number of shares sold (in shares)		2.5		11.5					14.0
Net proceeds from sale of equity investment		$ 50		$ 200					$ 250
Gain on sale				$ 102
Goodwill impairment loss							$ 1,200
Other-than-temporary impairment loss						$ 2,700
Equity Method Investment, Nonconsolidated Investee
Equity Method Investments
Equity method investment amounts		2,938							2,938
Equity-method investments financial information summarized by Income Statement line item
Revenues and other income									6,252	5,455	26,520
Costs and expenses									4,569	5,455	24,084
Net income									1,683	0	2,436
Equity-method investments financial information summarized by Balance Sheet line item
Current assets		3,387							3,387	1,419	1,130
Non-current assets		19,341							19,341	18,693	21,158
Current liabilities		1,976							1,976	1,549	785
Long-term debt		9,464							9,464	7,860	8,673
Other non-current liabilities		1,187							1,187	866	859
Stockholders’ equity		10,101							10,101	9,837	11,971
Anadarko Petroleum Corporation
Equity Method Investments
Equity method investment amounts		2,900							2,900
WES
Equity Method Investments
Equity method investment amounts		2,000							$ 2,000
Goodwill impairment loss										$ 1,200
Other-than-temporary impairment loss								$ 2,700
RELATED-PARTY TRANSACTIONS
Sales to related party (as a percent)									58.00%	70.00%
Purchases from related party (as a percent)									27.00%	59.00%
WES | Equity Method Investment, Nonconsolidated Investee
Equity Method Investments
Equity method investment amounts		$ 1,963							$ 1,963
Equity method investment ownership percentage		51.80%							51.80%
OxyChem Ingleside Facility | Equity Method Investment, Nonconsolidated Investee
Equity Method Investments
Equity method investment amounts		$ 599							$ 599
Equity method investment ownership percentage		50.00%							50.00%
OLCV - Related | Equity Method Investment, Nonconsolidated Investee
Equity Method Investments
Equity method investment amounts		$ 164							$ 164
Other | Equity Method Investment, Nonconsolidated Investee
Equity Method Investments
Equity method investment amounts		212							212
Dolphin Energy Limited
Equity Method Investments
Equity method investment amounts		$ 217							$ 217
Equity method investment ownership percentage		24.50%							24.50%
Cash distributions			$ 560
Dividends received as return on investment			110
Excess distributions			$ 450
Carrying value of investment and excess distributions		$ 233							$ 233
Plains All American Pipeline, LP
Equity Method Investments
Net proceeds from sale of equity investment					$ 646
Equity-method investments financial information summarized by Balance Sheet line item
Investment gross revenue											$ 24,700
General Partner of Plains All American Pipeline, L.P
RELATED-PARTY TRANSACTIONS
Sales to related party (as a percent)											87.00%
Ingleside Ethylene LLC
RELATED-PARTY TRANSACTIONS
Purchases from related party (as a percent)									70.00%	41.00%	98.00%

[1] Included $504 million and $316 million of finance lease liabilities as of December 31, 2021, and 2020, respectively.