Income Taxes	6 Months Ended
	Jun. 30, 2022
Income Tax Disclosure [Abstract]
Income Taxes	Income TaxesAWR's effective income tax rate (“ETR”) was 23.7% and 21.9% for the three months ended June 30, 2022 and 2021, respectively, and was 23.8% and 22.6% for the six months ended June 30, 2022 and 2021, respectively. GSWC's ETR was 25.5% and 22.1% for the three months ended June 30, 2022 and 2021, respectively, and was 24.9% and 22.7% for the six months ended June 30, 2022 and 2021, respectively.The AWR and GSWC effective tax rates differed from the federal corporate statutory tax rate of 21% primarily due to (i) state taxes; (ii) permanent differences, including the excess tax benefits from share-based payments, which were reflected in the income statements and resulted in a reduction to income tax expense during the three and six months ended June 30, 2022 and 2021; (iii) the ongoing amortization of the excess deferred income tax liability; and (iv) differences between book and taxable income that are treated as flow-through adjustments in accordance with regulatory requirements (principally from plant, rate-case, and compensation-related items). As a regulated utility, GSWC treats certain temporary differences as flow-through in computing its income tax expense consistent with the income tax method used in its CPUC-jurisdiction ratemaking. Flow-through items either increase or decrease tax expense and thus impact the ETR.