SCHEDULE I - CONDENSED FINANCIAL INFORMATION OF REGISTRANT - Balance Sheets (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Current assets
Cash and cash equivalents	$ 9,969	$ 59,968
Accounts receivable	391,923	313,576
Income tax receivable	7,514	6,792
Other current assets	83,896	76,627
Total current assets	1,551,100	1,198,319
Investments and other assets
Other assets	97,884	91,104
Total investments and other assets	1,797,959	1,485,866
Total Assets	22,003,222	20,020,421
Current liabilities
Accounts payable	393,083	318,585
Accrued taxes	168,645	159,551
Common dividends payable	95,988	93,531
Short-term borrowings	292,000	169,000
Current maturities of long-term debt	150,000	0
Operating lease liabilities	100,443	74,785
Other current liabilities	151,968	187,448
Total current liabilities	1,756,869	1,360,433
Deferred credits and other
Long-term debt less current maturities (Note 7)	6,913,735	6,314,266
Operating lease liabilities	728,401	361,336
Other	232,914	190,643
Total deferred credits and other	7,311,158	6,592,929
COMMITMENTS AND CONTINGENCIES (SEE NOTES)
Common stock equity
Common stock	2,702,743	2,677,482
Accumulated other comprehensive loss	(54,861)	(62,796)
Retained earnings	3,264,719	3,025,106
Total shareholders’ equity	5,906,200	5,633,503
Noncontrolling interests	115,260	119,290
Total equity	6,021,460	5,752,793	$ 5,553,188	$ 5,348,705
Total Liabilities and Equity	22,003,222	20,020,421
Pinnacle West
Current assets
Cash and cash equivalents	594	19
Accounts receivable	125,457	123,980
Income tax receivable	1,498	14,719
Other current assets	13	298
Total current assets	127,562	139,016
Investments and other assets
Investments in subsidiaries	6,797,528	6,400,339
Deferred income taxes	19,520	7,589
Other assets	57,608	52,595
Total investments and other assets	6,874,656	6,460,523
Total Assets	7,002,218	6,599,539
Current liabilities
Accounts payable	3,071	5,669
Accrued taxes	19,855	16,998
Common dividends payable	95,988	93,531
Short-term borrowings	13,300	169,000
Current maturities of long-term debt	150,000	0
Operating lease liabilities	107	90
Other current liabilities	14,684	15,306
Total current liabilities	297,005	300,594
Deferred credits and other
Long-term debt less current maturities (Note 7)	647,139	496,321
Pension liabilities	14,537	17,541
Operating lease liabilities	1,576	1,683
Other	20,501	30,607
Total deferred credits and other	36,614	49,831
COMMITMENTS AND CONTINGENCIES (SEE NOTES)
Common stock equity
Common stock	2,696,342	2,671,193
Accumulated other comprehensive loss	(54,861)	(62,796)
Retained earnings	3,264,719	3,025,106
Total shareholders’ equity	5,906,200	5,633,503
Noncontrolling interests	115,260	119,290
Total equity	6,021,460	5,752,793
Total Liabilities and Equity	$ 7,002,218	$ 6,599,539