Regulatory Matters 4 (Details) - USD ($) $ in Millions	1 Months Ended		12 Months Ended
	Oct. 31, 2005	Jul. 31, 2005	Dec. 31, 2020
GSWC | Costs deferred for future recovery on Aerojet case
Regulatory matters:
Increase in Revenue Requirement, Recoverable through Surcharges		$ 21.3
Recovery period		20 years
Reimbursement to recover costs			$ 17.5
GSWC | Costs deferred for future recovery on Aerojet case | Maximum
Regulatory matters:
Recovery period	20 years
GSWC | Water Revenue Adjustment Mechanism Net of Modified Cost Balancing Account [Member] | Maximum
Regulatory matters:
Recovery period			24 months
Bear Valley Electric Service, Inc. | Renewables Portfolio Standard [Member]
Regulatory matters:
Derivative, Term of Contract			ten