Commitments and Contingencies (Details) $ in Millions	12 Months Ended
	Dec. 31, 2019 USD ($)
Commitments for demand charges under existing long-term contracts and binding precedent agreements with various pipelines
Remedial action included in other credits	$ 12.1
Pipeline Demand Charges
Commitments for demand charges under existing long-term contracts and binding precedent agreements with various pipelines
Amount due as of the balance sheet date	22,500.0
Amount due in 2020	1,400.0
Amount due in 2021	1,800.0
Amount due in 2022	1,800.0
Amount due in 2023	1,700.0
Amount due in 2024	1,700.0
Amount due thereafter	14,100.0
Frac Sand and Equipment
Commitments for demand charges under existing long-term contracts and binding precedent agreements with various pipelines
Amount due in 2020	104.3
Amount due in 2021	36.8
Amount due in 2022	$ 2.0