Revenue (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	$ 609	$ 1,671	$ 1,896	$ 3,228
Other operating revenues	224	(11)	291	4
Total sales and other operating revenues	833	1,660	2,187	3,232
Crude oil revenue
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	300	967	1,041	1,777
Natural gas liquids revenue
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	43	48	91	116
Natural gas revenue
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	123	195	304	426
Sales of purchased oil and gas
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	143	461	460	909
Exploration and Production
Disaggregation of Revenue [Line Items]
Total sales and other operating revenues	833	1,660	2,187	3,232
Exploration and Production | Crude oil revenue
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	300	967	1,041	1,777
Exploration and Production | Crude oil revenue | United States
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	254	762	919	1,444
Exploration and Production | Crude oil revenue | Guyana
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	31	0	69	0
Exploration and Production | Crude oil revenue | Malaysia & JDA
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	1	24	3	45
Exploration and Production | Crude oil revenue | Denmark
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	14	51	50	67
Exploration and Production | Crude oil revenue | Libya
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	130	0	221
Exploration and Production | Natural gas liquids revenue
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	43	48	91	116
Exploration and Production | Natural gas liquids revenue | United States
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	43	48	91	116
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 | Denmark
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0	0
Exploration and Production | Natural gas liquids revenue | Libya
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	123	195	304	426
Exploration and Production | Natural gas revenue | United States
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	32	33	70	75
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	89	154	228	334
Exploration and Production | Natural gas revenue | Denmark
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	2	2	4	5
Exploration and Production | Natural gas revenue | Libya
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	6	2	12
Exploration and Production | Sales of purchased oil and gas
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	143	461	460	909
Exploration and Production | Sales of purchased oil and gas | United States
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	143	439	459	865
Exploration and Production | Sales of purchased oil and gas | Guyana
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	1	0
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 | Denmark
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0	0
Exploration and Production | Sales of purchased oil and gas | Libya
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	22	0	44
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
Operating Segments | Exploration and Production
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	609	1,671	1,896	3,228
Other operating revenues	224	(11)	291	4
Total sales and other operating revenues	833	1,660	2,187	3,232
Operating Segments | Exploration and Production | United States
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	472	1,282	1,539	2,500
Other operating revenues	188	(11)	243	4
Total sales and other operating revenues	660	1,271	1,782	2,504
Operating Segments | Exploration and Production | Guyana
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	31	0	70	0
Other operating revenues	27	0	33	0
Total sales and other operating revenues	58	0	103	0
Operating Segments | Exploration and Production | Malaysia & JDA
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	90	178	231	379
Other operating revenues	0	0	1	0
Total sales and other operating revenues	90	178	232	379
Operating Segments | Exploration and Production | Denmark
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	16	53	54	72
Other operating revenues	9	0	14	0
Total sales and other operating revenues	25	53	68	72
Operating Segments | Exploration and Production | Libya
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	158	2	277
Other operating revenues	0	0	0	0
Total sales and other operating revenues	0	158	2	277
Operating Segments | Midstream
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	270	190	561	380
Other operating revenues	0	0	0	0
Total sales and other operating revenues	270	190	561	380
Eliminations
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	(270)	(190)	(561)	(380)
Other operating revenues	0	0	0	0
Total sales and other operating revenues	(270)	(190)	(561)	(380)
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 | Denmark
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0	0
Eliminations | Exploration and Production | Libya
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	270	190	561	380
Total sales and other operating revenues	$ 270	$ 190	$ 561	$ 380