Segment Information - Reconciliation to Adjusted EBITDA (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Segment Reporting Information [Line Items]
Income from continuing operations, net of income taxes	$ 204.1	$ 411.3	$ 488.2	$ 291.5
Depreciation, depletion and amortization	80.6	73.8	156.9	146.7
Asset retirement obligation expenses	15.5	12.7	30.9	27.7
Restructuring charges	2.0	0.2	2.1	1.8
Asset impairment	0.0	0.0	2.0	0.0
Provision for NARM and Shoal Creek loss	33.7	0.0	33.7	0.0
Changes in amortization of basis difference related to equity affiliates	(0.4)	(0.6)	(0.7)	(1.2)
Interest expense	13.3	37.6	31.7	77.0
Net loss on early debt extinguishment	2.0	2.3	8.8	25.8
Interest income	(23.1)	(0.9)	(36.2)	(1.4)
Unrealized (gains) losses on derivative contracts related to forecasted sales	(40.3)	24.5	(159.0)	325.5
Unrealized (gains) losses on foreign currency option contracts	(2.8)	6.3	(0.6)	3.0
Take-or-pay contract-based intangible recognition	(0.6)	(0.7)	(1.2)	(1.4)
Income tax provision	74.2	11.3	192.2	10.3
Adjusted EBITDA	$ 358.2	$ 577.8	$ 748.8	$ 905.3