Commitments and Contingencies (Details) $ in Millions	6 Months Ended
	Jun. 30, 2020 USD ($)
Other Commitments [Line Items]
Purchase orders outstanding	$ 5.5
Purchase orders outstanding, term	5 months
Performance Guarantee [Member]
Other Commitments [Line Items]
Bonds outstanding	$ 1,079.0
Estimated remaining costs for bonded projects	452.0
Contingencies Excluding Wildfire and Health Insurance [Member]
Other Commitments [Line Items]
Insurance coverage deductible	1.0
Wildfire [Member]
Other Commitments [Line Items]
Insurance coverage deductible	2.0
Health Insurance [Member]
Other Commitments [Line Items]
Insurance coverage deductible	$ 0.2