Revenue (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	$ 1,646	$ 609	$ 3,593	$ 1,896
Other operating revenues	(67)	224	(116)	291
Total sales and other operating revenues	1,579	833	3,477	2,187
Crude oil revenue
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	957	300	2,161	1,041
Natural gas liquids revenue
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	120	43	263	91
Natural gas revenue
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	240	123	519	304
Sales of purchased oil and gas
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	329	143	650	460
Exploration and Production
Disaggregation of Revenue [Line Items]
Total sales and other operating revenues	1,579	833	3,477	2,187
Exploration and Production | Crude oil revenue
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	957	300	2,161	1,041
Exploration and Production | Crude oil revenue | United States
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	661	254	1,546	919
Exploration and Production | Crude oil revenue | Guyana
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	134	31	315	69
Exploration and Production | Crude oil revenue | Malaysia & JDA
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	27	1	49	3
Exploration and Production | Crude oil revenue | Other
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	135	14	251	50
Exploration and Production | Natural gas liquids revenue
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	120	43	263	91
Exploration and Production | Natural gas liquids revenue | United States
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	120	43	263	91
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	240	123	519	304
Exploration and Production | Natural gas revenue | United States
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	61	32	174	70
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	178	89	341	228
Exploration and Production | Natural gas revenue | Other
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	1	2	4	6
Exploration and Production | Sales of purchased oil and gas
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	329	143	650	460
Exploration and Production | Sales of purchased oil and gas | United States
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	299	143	597	459
Exploration and Production | Sales of purchased oil and gas | Guyana
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	4	0	8	1
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	26	0	45	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	(294)	(270)	(583)	(561)
Other operating revenues	0	0	0	0
Total sales and other operating revenues	(294)	(270)	(583)	(561)
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	294	270	583	561
Total sales and other operating revenues	294	270	583	561
Operating Segments | Exploration and Production
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	1,646	609	3,593	1,896
Other operating revenues	(67)	224	(116)	291
Total sales and other operating revenues	1,579	833	3,477	2,187
Operating Segments | Exploration and Production | United States
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	1,141	472	2,580	1,539
Other operating revenues	(53)	188	(94)	243
Total sales and other operating revenues	1,088	660	2,486	1,782
Operating Segments | Exploration and Production | Guyana
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	138	31	323	70
Other operating revenues	(6)	27	(10)	33
Total sales and other operating revenues	132	58	313	103
Operating Segments | Exploration and Production | Malaysia & JDA
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	205	90	390	231
Other operating revenues	0	0	0	1
Total sales and other operating revenues	205	90	390	232
Operating Segments | Exploration and Production | Other
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	162	16	300	56
Other operating revenues	(8)	9	(12)	14
Total sales and other operating revenues	154	25	288	70
Operating Segments | Midstream
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	294	270	583	561
Other operating revenues	0	0	0	0
Total sales and other operating revenues	$ 294	$ 270	$ 583	$ 561