Income Taxes - Book Income Reconciliation To Income Tax Expense (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Effective Income Tax Rate Reconciliation, Amount [Abstract]
Expected income tax benefit (expense) based on federal statutory tax rate	$ (10.0)	$ 58.5	$ 233.6
State income tax benefit (expense), net of federal benefit	(1.4)	6.5	27.0
Unit-based compensation	(3.1)	(6.0)	(2.2)
Non-deductible expense related to impairments	0.0	(43.4)	(264.5)
Statutory rate changes	(10.2)	0.0	0.0
Change in valuation allowance	(1.7)	153.3	0.0
Other	(2.4)	(5.5)	(0.8)
Total income tax expense	(25.4)	$ (143.2)	$ (6.9)
Oklahoma
Effective Income Tax Rate Reconciliation, Amount [Abstract]
Deferred state income tax expense (benefit)	7.6
Louisiana
Effective Income Tax Rate Reconciliation, Amount [Abstract]
Deferred state income tax expense (benefit)	$ 2.6