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Retirement Plans and Other Postretirement Benefits - Schedule of Fair Value of Pinnacle West's Pension Plan (Details) - USD ($) $ in Thousands | Dec. 31, 2024 | Dec. 31, 2023 | Dec. 31, 2022
--- | --- | --- | ---
Pension Plans |  |  |
Fair value of Pinnacle West's pension plan and other postretirement benefit plan assets, by asset category |  |  |
Other | $ 432,742 | $ 399,298 |
Fair value of plan assets | 2,639,862 | 2,835,549 | $ 2,829,485
Pension Plans | Level 1 |  |  |
Fair value of Pinnacle West's pension plan and other postretirement benefit plan assets, by asset category |  |  |
Gross fair value of plan assets | 748,033 | 885,721 |
Pension Plans | Level 2 |  |  |
Fair value of Pinnacle West's pension plan and other postretirement benefit plan assets, by asset category |  |  |
Gross fair value of plan assets | 1,459,087 | 1,550,530 |
Other Benefits Plans |  |  |
Fair value of Pinnacle West's pension plan and other postretirement benefit plan assets, by asset category |  |  |
Other | 165,813 | 107,201 |
Fair value of plan assets | 702,192 | 696,494 | $ 652,287
Other Benefits Plans | Level 1 |  |  |
Fair value of Pinnacle West's pension plan and other postretirement benefit plan assets, by asset category |  |  |
Gross fair value of plan assets | 337,359 | 391,019 |
Other Benefits Plans | Level 2 |  |  |
Fair value of Pinnacle West's pension plan and other postretirement benefit plan assets, by asset category |  |  |
Gross fair value of plan assets | 199,020 | 198,274 |
Cash and cash equivalents | Pension Plans |  |  |
Fair value of Pinnacle West's pension plan and other postretirement benefit plan assets, by asset category |  |  |
Other | 0 |  |
Fair value of plan assets | 9,055 |  |
Cash and cash equivalents | Pension Plans | Level 1 |  |  |
Fair value of Pinnacle West's pension plan and other postretirement benefit plan assets, by asset category |  |  |
Gross fair value of plan assets | 9,055 |  |
Cash and cash equivalents | Pension Plans | Level 2 |  |  |
Fair value of Pinnacle West's pension plan and other postretirement benefit plan assets, by asset category |  |  |
Gross fair value of plan assets | 0 |  |
Cash and cash equivalents | Other Benefits Plans |  |  |
Fair value of Pinnacle West's pension plan and other postretirement benefit plan assets, by asset category |  |  |
Other | 0 |  |
Fair value of plan assets | 840 |  |
Cash and cash equivalents | Other Benefits Plans | Level 1 |  |  |
Fair value of Pinnacle West's pension plan and other postretirement benefit plan assets, by asset category |  |  |
Gross fair value of plan assets | 840 |  |
Cash and cash equivalents | Other Benefits Plans | Level 2 |  |  |
Fair value of Pinnacle West's pension plan and other postretirement benefit plan assets, by asset category |  |  |
Gross fair value of plan assets | 0 |  |
Corporate | Pension Plans |  |  |
Fair value of Pinnacle West's pension plan and other postretirement benefit plan assets, by asset category |  |  |
Other | 0 | 0 |
Fair value of plan assets | 1,325,833 | 1,415,346 |
Corporate | Pension Plans | Level 1 |  |  |
Fair value of Pinnacle West's pension plan and other postretirement benefit plan assets, by asset category |  |  |
Gross fair value of plan assets | 0 | 0 |
Corporate | Pension Plans | Level 2 |  |  |
Fair value of Pinnacle West's pension plan and other postretirement benefit plan assets, by asset category |  |  |
Gross fair value of plan assets | 1,325,833 | 1,415,346 |
Corporate | Other Benefits Plans |  |  |
Fair value of Pinnacle West's pension plan and other postretirement benefit plan assets, by asset category |  |  |
Other | 0 | 0 |
Fair value of plan assets | 186,435 | 189,902 |
Corporate | Other Benefits Plans | Level 1 |  |  |
Fair value of Pinnacle West's pension plan and other postretirement benefit plan assets, by asset category |  |  |
Gross fair value of plan assets | 0 | 0 |
Corporate | Other Benefits Plans | Level 2 |  |  |
Fair value of Pinnacle West's pension plan and other postretirement benefit plan assets, by asset category |  |  |
Gross fair value of plan assets | 186,435 | 189,902 |
U.S. Treasury | Pension Plans |  |  |
Fair value of Pinnacle West's pension plan and other postretirement benefit plan assets, by asset category |  |  |
Other | 0 | 0 |
Fair value of plan assets | 561,317 | 622,273 |
U.S. Treasury | Pension Plans | Level 1 |  |  |
Fair value of Pinnacle West's pension plan and other postretirement benefit plan assets, by asset category |  |  |
Gross fair value of plan assets | 561,317 | 622,273 |
U.S. Treasury | Pension Plans | Level 2 |  |  |
Fair value of Pinnacle West's pension plan and other postretirement benefit plan assets, by asset category |  |  |
Gross fair value of plan assets | 0 | 0 |
U.S. Treasury | Other Benefits Plans |  |  |
Fair value of Pinnacle West's pension plan and other postretirement benefit plan assets, by asset category |  |  |
Other | 0 | 0 |
Fair value of plan assets | 204,274 | 207,665 |
U.S. Treasury | Other Benefits Plans | Level 1 |  |  |
Fair value of Pinnacle West's pension plan and other postretirement benefit plan assets, by asset category |  |  |
Gross fair value of plan assets | 204,274 | 207,665 |
U.S. Treasury | Other Benefits Plans | Level 2 |  |  |
Fair value of Pinnacle West's pension plan and other postretirement benefit plan assets, by asset category |  |  |
Gross fair value of plan assets | 0 | 0 |
Other | Pension Plans |  |  |
Fair value of Pinnacle West's pension plan and other postretirement benefit plan assets, by asset category |  |  |
Other | 0 | 0 |
Fair value of plan assets | 133,254 | 135,184 |
Other | Pension Plans | Level 1 |  |  |
Fair value of Pinnacle West's pension plan and other postretirement benefit plan assets, by asset category |  |  |
Gross fair value of plan assets | 0 | 0 |
Other | Pension Plans | Level 2 |  |  |
Fair value of Pinnacle West's pension plan and other postretirement benefit plan assets, by asset category |  |  |
Gross fair value of plan assets | 133,254 | 135,184 |
Other | Other Benefits Plans |  |  |
Fair value of Pinnacle West's pension plan and other postretirement benefit plan assets, by asset category |  |  |
Other | 0 | 0 |
Fair value of plan assets | 12,585 | 8,372 |
Other | Other Benefits Plans | Level 1 |  |  |
Fair value of Pinnacle West's pension plan and other postretirement benefit plan assets, by asset category |  |  |
Gross fair value of plan assets | 0 | 0 |
Other | Other Benefits Plans | Level 2 |  |  |
Fair value of Pinnacle West's pension plan and other postretirement benefit plan assets, by asset category |  |  |
Gross fair value of plan assets | 12,585 | 8,372 |
Common stock equities | Pension Plans |  |  |
Fair value of Pinnacle West's pension plan and other postretirement benefit plan assets, by asset category |  |  |
Other | 0 | 0 |
Fair value of plan assets | 74,939 | 150,657 |
Common stock equities | Pension Plans | Level 1 |  |  |
Fair value of Pinnacle West's pension plan and other postretirement benefit plan assets, by asset category |  |  |
Gross fair value of plan assets | 74,939 | 150,657 |
Common stock equities | Pension Plans | Level 2 |  |  |
Fair value of Pinnacle West's pension plan and other postretirement benefit plan assets, by asset category |  |  |
Gross fair value of plan assets | 0 | 0 |
Common stock equities | Other Benefits Plans |  |  |
Fair value of Pinnacle West's pension plan and other postretirement benefit plan assets, by asset category |  |  |
Other | 0 | 0 |
Fair value of plan assets | 89,685 | 139,952 |
Common stock equities | Other Benefits Plans | Level 1 |  |  |
Fair value of Pinnacle West's pension plan and other postretirement benefit plan assets, by asset category |  |  |
Gross fair value of plan assets | 89,685 | 139,952 |
Common stock equities | Other Benefits Plans | Level 2 |  |  |
Fair value of Pinnacle West's pension plan and other postretirement benefit plan assets, by asset category |  |  |
Gross fair value of plan assets | 0 | 0 |
Mutual funds | Pension Plans |  |  |
Fair value of Pinnacle West's pension plan and other postretirement benefit plan assets, by asset category |  |  |
Other | 0 | 0 |
Fair value of plan assets | 102,722 | 112,791 |
Mutual funds | Pension Plans | Level 1 |  |  |
Fair value of Pinnacle West's pension plan and other postretirement benefit plan assets, by asset category |  |  |
Gross fair value of plan assets | 102,722 | 112,791 |
Mutual funds | Pension Plans | Level 2 |  |  |
Fair value of Pinnacle West's pension plan and other postretirement benefit plan assets, by asset category |  |  |
Gross fair value of plan assets | 0 | 0 |
Mutual funds | Other Benefits Plans |  |  |
Fair value of Pinnacle West's pension plan and other postretirement benefit plan assets, by asset category |  |  |
Other | 0 | 0 |
Fair value of plan assets | 23,415 | 22,256 |
Mutual funds | Other Benefits Plans | Level 1 |  |  |
Fair value of Pinnacle West's pension plan and other postretirement benefit plan assets, by asset category |  |  |
Gross fair value of plan assets | 23,415 | 22,256 |
Mutual funds | Other Benefits Plans | Level 2 |  |  |
Fair value of Pinnacle West's pension plan and other postretirement benefit plan assets, by asset category |  |  |
Gross fair value of plan assets | 0 | 0 |
Equities | Pension Plans |  |  |
Fair value of Pinnacle West's pension plan and other postretirement benefit plan assets, by asset category |  |  |
Other | 244,734 | 192,945 |
Fair value of plan assets | 244,734 | 192,945 |
Equities | Pension Plans | Level 1 |  |  |
Fair value of Pinnacle West's pension plan and other postretirement benefit plan assets, by asset category |  |  |
Gross fair value of plan assets | 0 | 0 |
Equities | Pension Plans | Level 2 |  |  |
Fair value of Pinnacle West's pension plan and other postretirement benefit plan assets, by asset category |  |  |
Gross fair value of plan assets | 0 | 0 |
Equities | Other Benefits Plans |  |  |
Fair value of Pinnacle West's pension plan and other postretirement benefit plan assets, by asset category |  |  |
Other | 140,178 | 81,724 |
Fair value of plan assets | 140,178 | 81,724 |
Equities | Other Benefits Plans | Level 1 |  |  |
Fair value of Pinnacle West's pension plan and other postretirement benefit plan assets, by asset category |  |  |
Gross fair value of plan assets | 0 | 0 |
Equities | Other Benefits Plans | Level 2 |  |  |
Fair value of Pinnacle West's pension plan and other postretirement benefit plan assets, by asset category |  |  |
Gross fair value of plan assets | 0 | 0 |
Real estate | Pension Plans |  |  |
Fair value of Pinnacle West's pension plan and other postretirement benefit plan assets, by asset category |  |  |
Other | 127,397 | 140,613 |
Fair value of plan assets | 127,397 | 140,613 |
Real estate | Pension Plans | Level 1 |  |  |
Fair value of Pinnacle West's pension plan and other postretirement benefit plan assets, by asset category |  |  |
Gross fair value of plan assets | 0 | 0 |
Real estate | Pension Plans | Level 2 |  |  |
Fair value of Pinnacle West's pension plan and other postretirement benefit plan assets, by asset category |  |  |
Gross fair value of plan assets | 0 | 0 |
Real estate | Other Benefits Plans |  |  |
Fair value of Pinnacle West's pension plan and other postretirement benefit plan assets, by asset category |  |  |
Other | 19,474 | 20,001 |
Fair value of plan assets | 19,474 | 20,001 |
Real estate | Other Benefits Plans | Level 1 |  |  |
Fair value of Pinnacle West's pension plan and other postretirement benefit plan assets, by asset category |  |  |
Gross fair value of plan assets | 0 | 0 |
Real estate | Other Benefits Plans | Level 2 |  |  |
Fair value of Pinnacle West's pension plan and other postretirement benefit plan assets, by asset category |  |  |
Gross fair value of plan assets | 0 | 0 |
Short-term investments and other | Pension Plans |  |  |
Fair value of Pinnacle West's pension plan and other postretirement benefit plan assets, by asset category |  |  |
Other | 60,611 | 65,740 |
Fair value of plan assets | 60,611 | 65,740 |
Short-term investments and other | Pension Plans | Level 1 |  |  |
Fair value of Pinnacle West's pension plan and other postretirement benefit plan assets, by asset category |  |  |
Gross fair value of plan assets | 0 | 0 |
Short-term investments and other | Pension Plans | Level 2 |  |  |
Fair value of Pinnacle West's pension plan and other postretirement benefit plan assets, by asset category |  |  |
Gross fair value of plan assets | 0 | 0 |
Short-term investments and other | Other Benefits Plans |  |  |
Fair value of Pinnacle West's pension plan and other postretirement benefit plan assets, by asset category |  |  |
Other | 6,161 | 5,476 |
Fair value of plan assets | 25,306 | 26,622 |
Short-term investments and other | Other Benefits Plans | Level 1 |  |  |
Fair value of Pinnacle West's pension plan and other postretirement benefit plan assets, by asset category |  |  |
Gross fair value of plan assets | 19,145 | 21,146 |
Short-term investments and other | Other Benefits Plans | Level 2 |  |  |
Fair value of Pinnacle West's pension plan and other postretirement benefit plan assets, by asset category |  |  |
Gross fair value of plan assets | $ 0 | $ 0 |

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