Commitments and Contingencies - Narrative (Details)	Sep. 20, 2018 subclass	Jan. 31, 2021 USD ($)
Loss Contingencies [Line Items]
Standby letters of credit		$ 151,000,000.0
Surety bonds		640,600,000
Energy Savings Contracts
Loss Contingencies [Line Items]
Guarantee obligation		173,800,000
Minimum
Loss Contingencies [Line Items]
Amount of reasonably possible loss		0
Maximum
Loss Contingencies [Line Items]
Amount of reasonably possible loss		5,000,000
Bucio
Loss Contingencies [Line Items]
Loss contingency, number of certified subclasses | subclass	4
Pending Litigation
Loss Contingencies [Line Items]
Loss contingency amount accrued for probable losses		$ 13,800,000