Revenue (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	$ 1,823	$ 1,015	$ 5,416	$ 2,911
Other operating revenues	(64)	144	(180)	435
Total sales and other operating revenues	1,759	1,159	5,236	3,346
Crude oil revenue
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	974	575	3,135	1,616
Natural gas liquids revenue
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	143	68	406	159
Natural gas revenue
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	222	151	741	455
Sales of purchased oil and gas
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	484	221	1,134	681
Exploration and Production
Disaggregation of Revenue [Line Items]
Total sales and other operating revenues	1,759	1,159	5,236	3,346
Exploration and Production | Crude oil revenue
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	974	575	3,135	1,616
Exploration and Production | Crude oil revenue | United States
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	654	471	2,200	1,390
Exploration and Production | Crude oil revenue | Guyana
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	214	80	529	149
Exploration and Production | Crude oil revenue | Malaysia & JDA
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	2	13	51	16
Exploration and Production | Crude oil revenue | Other
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	104	11	355	61
Exploration and Production | Natural gas liquids revenue
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	143	68	406	159
Exploration and Production | Natural gas liquids revenue | United States
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	143	68	406	159
Exploration and Production | Natural gas liquids revenue | Guyana
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0	0
Exploration and Production | Natural gas liquids revenue | Malaysia & JDA
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0	0
Exploration and Production | Natural gas liquids revenue | Other
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0	0
Exploration and Production | Natural gas revenue
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	222	151	741	455
Exploration and Production | Natural gas revenue | United States
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	77	34	251	104
Exploration and Production | Natural gas revenue | Guyana
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0	0
Exploration and Production | Natural gas revenue | Malaysia & JDA
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	143	116	484	344
Exploration and Production | Natural gas revenue | Other
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	2	1	6	7
Exploration and Production | Sales of purchased oil and gas
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	484	221	1,134	681
Exploration and Production | Sales of purchased oil and gas | United States
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	457	220	1,054	679
Exploration and Production | Sales of purchased oil and gas | Guyana
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	4	1	12	2
Exploration and Production | Sales of purchased oil and gas | Malaysia & JDA
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0	0
Exploration and Production | Sales of purchased oil and gas | Other
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	23	0	68	0
Midstream
Disaggregation of Revenue [Line Items]
Total sales and other operating revenues	0	0	0	0
Midstream | Crude oil revenue
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0	0
Midstream | Natural gas liquids revenue
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0	0
Midstream | Natural gas revenue
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0	0
Midstream | Sales of purchased oil and gas
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0	0
Eliminations
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	(304)	(264)	(887)	(825)
Other operating revenues	0	0	0	0
Total sales and other operating revenues	(304)	(264)	(887)	(825)
Eliminations | Exploration and Production
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0	0
Total sales and other operating revenues	0	0	0	0
Eliminations | Exploration and Production | United States
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0	0
Eliminations | Exploration and Production | Guyana
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0	0
Eliminations | Exploration and Production | Malaysia & JDA
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0	0
Eliminations | Exploration and Production | Other
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0	0
Eliminations | Midstream
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	304	264	887	825
Total sales and other operating revenues	304	264	887	825
Operating Segments | Exploration and Production
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	1,823	1,015	5,416	2,911
Other operating revenues	(64)	144	(180)	435
Total sales and other operating revenues	1,759	1,159	5,236	3,346
Operating Segments | Exploration and Production | United States
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	1,331	793	3,911	2,332
Other operating revenues	(51)	125	(145)	368
Total sales and other operating revenues	1,280	918	3,766	2,700
Operating Segments | Exploration and Production | Guyana
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	218	81	541	151
Other operating revenues	(9)	18	(19)	51
Total sales and other operating revenues	209	99	522	202
Operating Segments | Exploration and Production | Malaysia & JDA
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	145	129	535	360
Other operating revenues	0	0	0	1
Total sales and other operating revenues	145	129	535	361
Operating Segments | Exploration and Production | Other
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	129	12	429	68
Other operating revenues	(4)	1	(16)	15
Total sales and other operating revenues	125	13	413	83
Operating Segments | Midstream
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	304	264	887	825
Other operating revenues	0	0	0	0
Total sales and other operating revenues	$ 304	$ 264	$ 887	$ 825