Long-Term Debt and Liquidity Matters - Fair Value of Long-Term Debt (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Estimated fair value of long-term debt, including current maturities
Carrying Amount	$ 3,819,971	$ 3,390,143
Fair Value	4,106,367	3,839,108
Pinnacle West
Estimated fair value of long-term debt, including current maturities
Carrying Amount	125,000	125,000
Fair Value	125,000	125,000
ARIZONA PUBLIC SERVICE COMPANY
Estimated fair value of long-term debt, including current maturities
Carrying Amount	3,694,971	3,265,143
Fair Value	$ 3,981,367	$ 3,714,108