Supplemental Oil and Gas Information - Narrative (Details) MMBbls in Millions	12 Months Ended
	Dec. 31, 2019 $ / bbl $ / Mcf MMBbls ft³	Dec. 31, 2018 $ / bbl $ / Mcf MMBbls ft³	Dec. 31, 2017 MMBbls ft³	Dec. 31, 2016 MMBbls ft³
Reserve Quantities [Line Items]
Future net cash flows annual discount factor, percentage	10.00%
U.S. statutory rate		21.00%	35.00%
Equity Method Investee
Reserve Quantities [Line Items]
Reserves attributable to investees accounted for my the equity method	0
Net crude oil and condensate revenue
Reserve Quantities [Line Items]
Average production costs per barrel of oil (in dollars per barrel) | $ / bbl	55.69	65.56
Proved undeveloped reserve development window		5 years	5 years
Associated assets, percentage interests acquired	80.00%
Net natural gas liquids revenue
Reserve Quantities [Line Items]
Proved reserves | MMBbls	56.1	54.2	48.9	42.5
Proved undeveloped reserve development window	5 years		5 years
Associated assets, percentage interests acquired	80.00%
Net natural gas revenue
Reserve Quantities [Line Items]
Average production costs per volume of natural gas (in dollars per cubic foot) | $ / Mcf	2.57	3.10
Proved reserves	2,069,700,000,000	2,143,600,000,000	1,927,100,000,000	1,878,000,000,000.0
Proved undeveloped reserve development window	5 years
Associated assets, percentage interests acquired	80.00%
Malaysia & Other | Net natural gas liquids revenue
Reserve Quantities [Line Items]
Proved reserves | MMBbls	0.0	0.7	0.3	0.5
Malaysia & Other | Net natural gas revenue
Reserve Quantities [Line Items]
Proved reserves	0	468,200,000,000	491,400,000,000	539,700,000,000
Canada | Net natural gas liquids revenue
Reserve Quantities [Line Items]
Proved reserves | MMBbls	3.3	5.9	5.6	5.6
Canada | Net natural gas revenue
Reserve Quantities [Line Items]
Proved reserves	1,652,900,000,000	1,366,400,000,000	1,212,400,000,000	1,118,900,000,000