APS - CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
PROPERTY, PLANT AND EQUIPMENT (Notes 1, 6 and 9)
Plant in service and held for future use	$ 24,211,167	$ 22,452,146
Accumulated depreciation and amortization	(8,408,040)	(7,929,878)
Net	15,803,127	14,522,268
Construction work in progress	1,724,004	1,882,791
Palo Verde sale leaseback, net of accumulated depreciation of $264,624 and $260,754 (Note 17)	86,426	90,296
Intangible assets, net of accumulated amortization of $884,371 and $816,827	267,110	258,880
Nuclear fuel, net of accumulated amortization of $118,074 and $126,157	99,490	100,119
Total property, plant and equipment	17,980,157	16,854,354
INVESTMENTS AND OTHER ASSETS
Nuclear decommissioning trusts (Notes 12 and 18)	1,201,246	1,073,410
Other special use funds (Notes 12 and 18)	362,781	347,231
Assets from risk management activities (Note 15)	0	44,394
Other assets	102,845	125,672
Total investments and other assets	1,666,872	1,590,707
CURRENT ASSETS
Cash and cash equivalents	4,955	4,832
Customer and other receivables	513,892	453,209
Accrued unbilled revenues	167,553	164,764
Allowance for doubtful accounts (Note 2)	(22,433)	(23,778)
Materials and supplies (at average cost)	444,344	410,481
Fossil fuel (at average cost)	49,203	40,155
Income tax receivable (Note 4)	332	14,086
Assets from risk management activities (Note 15)	6,808	87,835
Deferred fuel and purchased power regulatory asset (Note 3)	463,195	460,561
Other regulatory assets (Note 3)	162,562	78,318
Other current assets	101,417	60,091
Total current assets	1,926,967	1,750,554
DEFERRED DEBITS
Regulatory assets (Notes 1, 3, 4 and 7)	1,390,279	1,283,221
Operating lease right-of-use assets (Note 8)	1,309,975	801,688
Assets for pension and other postretirement benefits (Note 7)	323,438	396,599
Other	63,465	46,282
Total deferred debits	3,087,157	2,527,790
TOTAL ASSETS	24,661,153	22,723,405
CAPITALIZATION
Retained earnings	3,466,317	3,360,347
Accumulated other comprehensive loss (Note 19)	(33,144)	(31,435)
Total shareholders’ equity	6,177,664	6,048,647
Noncontrolling interests (Note 17)	107,198	111,229
Total equity	6,284,862	6,159,876
Long-term debt less current maturities (Note 6)	7,540,622	7,741,286
CURRENT LIABILITIES
Short-term borrowings (Note 5)	609,500	340,720
Accounts payable	442,455	430,425
Accrued taxes	166,833	164,440
Accrued interest	72,916	61,217
Common dividends payable	99,813	97,895
Customer deposits	42,037	41,769
Liabilities from risk management activities (Note 15)	80,913	37,697
Liabilities for asset retirements (Note 11)	28,550	12,232
Operating lease liabilities (Note 8)	67,883	105,210
Regulatory liabilities (Note 3)	209,923	271,575
Other current liabilities	193,524	148,276
Total current liabilities	2,889,347	1,762,141
DEFERRED CREDITS AND OTHER
Deferred income taxes (Note 4)	2,416,480	2,384,421
Regulatory liabilities (Notes 1, 3, 4 and 7)	1,965,865	2,061,776
Liabilities for asset retirements (Note 11)	937,451	785,530
Liabilities for pension benefits (Note 7)	112,702	116,286
Customer advances	533,580	422,103
Coal mine reclamation	184,007	179,255
Deferred investment tax credit	257,743	180,677
Unrecognized tax benefits (Note 4)	33,861	38,658
Operating lease liabilities (Note 8)	1,210,189	639,247
Other	251,469	247,400
Total deferred credits and other	7,946,322	7,060,102
COMMITMENTS AND CONTINGENCIES (Note 10)
TOTAL LIABILITIES AND EQUITY	24,661,153	22,723,405
Current maturities of long-term debt (Note 6)	875,000	50,685
Liabilities from risk management activities (Note 15)	42,975	4,749
Arizona Public Service Company
PROPERTY, PLANT AND EQUIPMENT (Notes 1, 6 and 9)
Plant in service and held for future use	24,207,706	22,448,685
Accumulated depreciation and amortization	(8,404,721)	(7,926,575)
Net	15,802,985	14,522,110
Construction work in progress	1,724,004	1,829,004
Palo Verde sale leaseback, net of accumulated depreciation of $264,624 and $260,754 (Note 17)	86,426	90,296
Intangible assets, net of accumulated amortization of $884,371 and $816,827	266,955	258,725
Nuclear fuel, net of accumulated amortization of $118,074 and $126,157	99,490	100,119
Total property, plant and equipment	17,979,860	16,800,254
INVESTMENTS AND OTHER ASSETS
Nuclear decommissioning trusts (Notes 12 and 18)	1,201,246	1,073,410
Other special use funds (Notes 12 and 18)	362,781	347,231
Assets from risk management activities (Note 15)	0	44,394
Other assets	43,625	43,344
Total investments and other assets	1,607,652	1,508,379
CURRENT ASSETS
Cash and cash equivalents	4,549	4,042
Customer and other receivables	510,296	448,880
Accrued unbilled revenues	167,553	164,764
Allowance for doubtful accounts (Note 2)	(22,433)	(23,778)
Materials and supplies (at average cost)	444,344	410,481
Fossil fuel (at average cost)	49,203	40,155
Income tax receivable (Note 4)	0	1,102
Assets from risk management activities (Note 15)	6,808	87,704
Deferred fuel and purchased power regulatory asset (Note 3)	463,195	460,561
Other regulatory assets (Note 3)	162,562	78,318
Other current assets	64,311	50,043
Total current assets	1,850,388	1,722,272
DEFERRED DEBITS
Regulatory assets (Notes 1, 3, 4 and 7)	1,390,279	1,283,221
Operating lease right-of-use assets (Note 8)	1,308,611	796,544
Assets for pension and other postretirement benefits (Note 7)	316,606	389,142
Other	63,059	44,040
Total deferred debits	3,078,555	2,512,947
TOTAL ASSETS	24,516,455	22,543,852
CAPITALIZATION
Common stock	178,162	178,162
Additional paid-in capital	3,321,696	3,171,696
Retained earnings	3,759,299	3,607,464
Accumulated other comprehensive loss (Note 19)	(17,219)	(15,596)
Total shareholders’ equity	7,241,938	6,941,726
Noncontrolling interests (Note 17)	107,198	111,229
Total equity	7,349,136	7,052,955
Long-term debt less current maturities (Note 6)	7,041,891	6,793,529
Total capitalization	14,391,027	13,846,484
CURRENT LIABILITIES
Short-term borrowings (Note 5)	532,850	325,000
Accounts payable	433,229	417,732
Accrued taxes	162,288	156,746
Accrued interest	72,548	60,518
Common dividends payable	99,800	97,900
Customer deposits	42,037	41,769
Liabilities from risk management activities (Note 15)	80,913	37,697
Liabilities for asset retirements (Note 11)	28,550	12,232
Operating lease liabilities (Note 8)	67,608	104,728
Regulatory liabilities (Note 3)	209,923	271,575
Other current liabilities	211,773	144,733
Total current liabilities	2,191,519	1,670,630
DEFERRED CREDITS AND OTHER
Deferred income taxes (Note 4)	2,431,697	2,385,647
Regulatory liabilities (Notes 1, 3, 4 and 7)	1,965,865	2,061,776
Liabilities for asset retirements (Note 11)	937,451	785,530
Liabilities for pension benefits (Note 7)	106,215	108,068
Customer advances	533,580	422,103
Coal mine reclamation	184,007	179,255
Deferred investment tax credit	257,743	180,677
Unrecognized tax benefits (Note 4)	33,861	38,658
Operating lease liabilities (Note 8)	1,208,857	634,199
Other	231,658	226,985
Total deferred credits and other	7,933,909	7,026,738
COMMITMENTS AND CONTINGENCIES (Note 10)
TOTAL LIABILITIES AND EQUITY	24,516,455	22,543,852
Current maturities of long-term debt (Note 6)	250,000	0
Liabilities from risk management activities (Note 15)	$ 42,975	$ 3,840