Regulatory Matters - Schedule of Regulatory Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Detail of regulatory assets
Total noncurrent regulatory assets	$ 1,822,100	$ 1,711,511
Less: current regulatory assets	538,879	518,524
Total noncurrent regulatory assets	1,283,221	1,192,987
Pension
Detail of regulatory assets
Total noncurrent regulatory assets	637,656	509,751
Deferred fuel and purchased power
Detail of regulatory assets
Total noncurrent regulatory assets	460,561	388,148
Income taxes — AFUDC equity
Detail of regulatory assets
Total noncurrent regulatory assets	179,631	172,393
Ocotillo deferral
Detail of regulatory assets
Total noncurrent regulatory assets	138,143	147,650
Retired power plant costs
Detail of regulatory assets
Total noncurrent regulatory assets	98,692	114,841
SCR deferral
Detail of regulatory assets
Total noncurrent regulatory assets	97,624	105,771
Deferred property taxes
Detail of regulatory assets
Total noncurrent regulatory assets	41,057	49,626
Deferred compensation
Detail of regulatory assets
Total noncurrent regulatory assets	33,660	33,997
Income taxes — investment tax credit basis adjustment
Detail of regulatory assets
Total noncurrent regulatory assets	23,977	24,768
Palo Verde VIEs (Note 17)
Detail of regulatory assets
Total noncurrent regulatory assets	20,933	21,094
Active union medical trust
Detail of regulatory assets
Total noncurrent regulatory assets	18,226	1,175
Four Corners cost deferral
Detail of regulatory assets
Total noncurrent regulatory assets	15,999	24,075
Navajo coal reclamation
Detail of regulatory assets
Total noncurrent regulatory assets	13,862	16,840
Lost fixed cost recovery
Detail of regulatory assets
Total noncurrent regulatory assets	9,547	63,889
Loss on reacquired debt
Detail of regulatory assets
Total noncurrent regulatory assets	9,468	11,020
Mead-Phoenix transmission line — contributions in aid of construction
Detail of regulatory assets
Total noncurrent regulatory assets	9,048	9,380
Tax expense adjustor mechanism
Detail of regulatory assets
Total noncurrent regulatory assets	5,845	6,501
Other
Detail of regulatory assets
Total noncurrent regulatory assets	$ 8,171	$ 10,592