Income Taxes - Reconciliation of Expected Federal Income Tax Benefit to Income Tax Provision (Benefit) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Expected income tax expense (benefit) at U.S. federal statutory rate	$ 77.7	$ (388.9)	$ (29.9)
Changes in valuation allowance, income tax	(101.3)	410.1	(32.0)
Changes in tax reserves	1.9	(7.7)	3.0
Excess depletion	(13.7)	(14.5)	(19.3)
Foreign earnings repatriation	0.0	0.0	76.1
Foreign earnings provision differential	17.3	16.4	45.6
Global intangible low-taxed income	67.0	0.0	6.1
Tax credits	(26.5)	0.0	0.0
Remeasurement of foreign income tax accounts	(1.8)	2.9	(0.1)
State income taxes, net of federal tax benefit	(1.1)	(6.8)	(13.2)
Other, net	3.3	(3.5)	9.7
Total income tax provision	$ 22.8	$ 8.0	$ 46.0