Commitments and Contingencies (Upstream Lighting Program) (Details) - USD ($) $ in Millions	1 Months Ended		12 Months Ended	36 Months Ended
	Mar. 31, 2021	Jan. 31, 2021	Dec. 31, 2018	Dec. 31, 2019	Dec. 31, 2021
Upstream Lighting Program
Loss Contingencies [Line Items]
Incentives paid to manufacturers				$ 91.0
Requested manufacturer incentives refund		$ 92.0
Fines		140.0
Remedy offered	$ 21.0
Upstream Lighting Program, ESPI
Loss Contingencies [Line Items]
Incentives received			$ 3.5
Incentives receivable					$ 1.3
CPUC requested award refund		$ 33.0