Summary of Significant Accounting Policies - Schedule of Reclassification of Prior Period Adjustments (Details) - USD ($)	Dec. 31, 2017	Dec. 31, 2016
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Pension and other postretirement benefits		$ 0
Derivative instruments		0
Total accumulated other comprehensive loss		0
Accumulated other comprehensive loss	$ (45,002,000)	(43,822,000)
As previously reported
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Pension and other postretirement benefits		(39,070,000)
Derivative instruments		(4,752,000)
Total accumulated other comprehensive loss		(43,822,000)
Accumulated other comprehensive loss		0
Reclassifications to conform to current year presentation
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Pension and other postretirement benefits		39,070,000
Derivative instruments		4,752,000
Total accumulated other comprehensive loss		43,822,000
Accumulated other comprehensive loss		(43,822,000)
ARIZONA PUBLIC SERVICE COMPANY
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Pension and other postretirement benefits		0
Derivative instruments		0
Total accumulated other comprehensive loss		0
Accumulated other comprehensive loss	$ (26,983,000)	(25,423,000)
ARIZONA PUBLIC SERVICE COMPANY | As previously reported
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Pension and other postretirement benefits		(20,671,000)
Derivative instruments		(4,752,000)
Total accumulated other comprehensive loss		(25,423,000)
Accumulated other comprehensive loss		0
ARIZONA PUBLIC SERVICE COMPANY | Reclassifications to conform to current year presentation
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Pension and other postretirement benefits		20,671,000
Derivative instruments		4,752,000
Total accumulated other comprehensive loss		25,423,000
Accumulated other comprehensive loss		$ (25,423,000)