Income Taxes	3 Months Ended
	Mar. 31, 2023
Income Tax Disclosure [Abstract]
Income Taxes	Income TaxesAWR’s effective income tax rate (“ETR”) was 23.8% and 24.0% for the three months ended March 31, 2023 and 2022, respectively. GSWC’s ETR was 24.5% and 23.9% for the three months ended March 31, 2023 and 2022, respectively.The AWR and GSWC ETRs differed from the federal corporate statutory tax rate of 21% primarily due to (i) state taxes; (ii) permanent differences, including certain tax effects from stock compensation; (iii) the ongoing amortization of the excess deferred income tax liability; and (iv) differences between book and taxable income that are treated as flowed-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 being flowed-through in computing its income tax expense consistent with the income tax method used in its CPUC-jurisdiction rate making. Flowed-through items either increase or decrease tax expense and thus impact the ETR.