Exit and Termination Costs - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
North Louisiana
Restructuring Cost And Reserve [Line Items]
Accretion expense			$ 33.0	$ 36.6
Exit and termination costs	$ 24.8	$ (28.2)
Total liability balance			401.2
Pennsylvania | Capacity Releases on Transportation Pipelines
Restructuring Cost And Reserve [Line Items]
Total liability balance			$ 5.7