Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Condensed Consolidated Statements of Comprehensive Income
Net Income (Loss)	$ 73,691	$ 181,007	$ 349,152	$ 860,443
Derivative instruments
Comprehensive income before tax				1,763
Other comprehensive income, derivative instruments, net of tax				1,763
Pension, postretirement and other post-employment benefits
Comprehensive loss before tax	(9,770)	(1,473)	(15,560)	(10,896)
Provision for income taxes	2,147		3,419
Other comprehensive loss, pension, postretirement and other post-employment benefits, net of tax	(7,623)	(1,473)	(12,141)	(10,896)
Available-for-sale securities
Comprehensive income (loss) before tax	54	(4)	15	178
Provision for income taxes	(12)		(4)
Other comprehensive (loss) income, available-for-sale securities, net of tax	42	(4)	11	178
Total other comprehensive loss	(7,581)	(1,477)	(12,130)	(8,955)
Total comprehensive income	$ 66,110	$ 179,530	$ 337,022	$ 851,488