Long-Term Debt and Liquidity Matters - Estimated Fair Value of Long-term Debt, Including Current Maturities (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Estimated fair value of long-term debt, including current maturities
Carrying Amount	$ 8,416,871	$ 8,415,622
Fair Value	7,468,208	7,555,653
APS
Estimated fair value of long-term debt, including current maturities
Carrying Amount	7,292,930	7,291,891
Fair Value	6,368,753	6,459,718
Pinnacle West
Estimated fair value of long-term debt, including current maturities
Carrying Amount	1,123,941	1,123,731
Fair Value	$ 1,099,455	$ 1,095,935