Property, Plant and Equipment (Narrative) (Details)	1 Months Ended	3 Months Ended		6 Months Ended
	Jun. 30, 2022 USD ($)	Jun. 30, 2021 USD ($)	Mar. 31, 2021 USD ($)	Jun. 30, 2022 USD ($) divestment	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)
Property, Plant and Equipment [Line Items]
Well costs	$ 178,421,000	$ 197,537,000		$ 178,421,000	$ 179,481,000	$ 181,616,000
Exploratory well costs capitalized more than one year	$ 174,200,000			174,200,000
Impairment of oil and gas Properties			$ 171,300,000	$ 0
Number of divestments (in divestments) | divestment				0
Proceeds from sale of oil and gas property and equipment			$ 267,700,000
Kodak field
Property, Plant and Equipment [Line Items]
Percentage of field acquired	11.00%			11.00%
Consideration transferred	$ 46,500,000
Lucius field
Property, Plant and Equipment [Line Items]
Percentage of field acquired		3.50%
Consideration transferred		$ 22,500,000
Terra Nova
Property, Plant and Equipment [Line Items]
Additional percentage acquired through commercial settlement					7.525%
Vietnam
Property, Plant and Equipment [Line Items]
Exploratory well costs capitalized more than one year	94,700,000			$ 94,700,000
United States
Property, Plant and Equipment [Line Items]
Exploratory well costs capitalized more than one year	48,500,000			48,500,000
MEXICO
Property, Plant and Equipment [Line Items]
Exploratory well costs capitalized more than one year	15,500,000			15,500,000
Brunei
Property, Plant and Equipment [Line Items]
Exploratory well costs capitalized more than one year	10,600,000			10,600,000
Canada
Property, Plant and Equipment [Line Items]
Exploratory well costs capitalized more than one year	$ 4,800,000			$ 4,800,000