Long-Term Debt and Liquidity Matters - Estimated Fair Value of Long-term Debt, Including Current Maturities (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Estimated fair value of long-term debt, including current maturities
Carrying Amount	$ 9,056,318	$ 8,415,622
Fair Value	8,467,840	7,555,653
APS
Estimated fair value of long-term debt, including current maturities
Carrying Amount	7,489,766	7,291,891
Fair Value	6,860,027	6,459,718
Pinnacle West
Estimated fair value of long-term debt, including current maturities
Carrying Amount	1,566,552	1,123,731
Fair Value	$ 1,607,813	$ 1,095,935