Retirement Plans and Other Benefits Retirement Plans and Other Benefits (Details)	1 Months Ended	12 Months Ended
	Jul. 31, 2012	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)	Dec. 31, 2012 USD ($)	Dec. 31, 2011 USD ($)	Jan. 01, 2015 Age
Plan Design Changes [Abstract]
Assets for other postretirement benefits		$ 185,997,000	$ 152,290,000
Amount of other postretirement benefit trust assets for union employee medical costs			100,000,000
Amount of pension and other postretirement benefit costs deferred					$ 14,000,000	$ 11,000,000
Regulatory asset amortization period	3 years
Amortization of regulatory assets		5,000,000	8,000,000	$ 8,000,000	$ 4,000,000
Change in mortality assumptions impact on pension and other postretirement obligations			67,000,000
Partnership funding commitments, contribution amount (up to)		75,000,000
Partnership funding commitments, funded amount		40,000,000
Pension Benefits
Plan Design Changes [Abstract]
Assets for other postretirement benefits		$ 0	0
Expected long-term return on plan assets for next fiscal year (as a percent)		6.90%
Contributions
Employer's contributions under the plan		$ 100,000,000	175,000,000	141,000,000
Minimum contributions under MAP-21
Minimum contributions under MAP-21		0
Voluntary employer contributions over next three years (up to)		$ 300,000,000
Pension Benefits | Fixed income securities
Target asset allocation
Target allocation (as a percent)		58.00%
Target allocation, minimum (as a percent)		55.00%
Target allocation, maximum (as a percent)		61.00%
Actual asset allocation (as a percent)		60.00%
Pension Benefits | Return-generating assets
Target asset allocation
Target allocation (as a percent)		42.00%
Target allocation, minimum (as a percent)		39.00%
Target allocation, maximum (as a percent)		45.00%
Actual asset allocation (as a percent)		40.00%
Pension Benefits | Developed equities
Target asset allocation
Target allocation (as a percent)		22.00%
Pension Benefits | Emerging equities
Target asset allocation
Target allocation (as a percent)		6.00%
Pension Benefits | Alternative investments
Target asset allocation
Target allocation (as a percent)		14.00%
Other postretirement benefits
Plan Design Changes [Abstract]
Age eligible for benefit | Age							65
Effect of plan amendment on net periodic benefit cost			10,000,000
Effect of plan amendment on expense			5,000,000
Effect of plan amendment on accumulated benefit obligation			316,000,000
Assets for other postretirement benefits		$ 185,997,000	152,290,000
Expected long-term return on plan assets for next fiscal year (as a percent)		4.74%
Contributions
Employer's contributions under the plan		$ 791,000	770,000	14,000,000
Expected employer contributions
2016		1,000,000
2017		1,000,000
2018		$ 1,000,000
Other postretirement benefits | Fixed income
Target asset allocation
Actual asset allocation (as a percent)		40.00%
Other postretirement benefits | Non-fixed income
Target asset allocation
Actual asset allocation (as a percent)		60.00%
Pinnacle West
Employee savings plan benefits
Expenses recorded for the defined contribution savings plan		$ 9,000,000	9,000,000	9,000,000
ARIZONA PUBLIC SERVICE COMPANY
Plan Design Changes [Abstract]
Assets for other postretirement benefits		$ 182,625,000	149,260,000
Employee savings plan benefits
APS's employees share of total cost of the plans (as a percent)		99.00%
ARIZONA PUBLIC SERVICE COMPANY | Pension Benefits
Contributions
Employer's contributions under the plan		$ 100,000,000	175,000,000	140,000,000
ARIZONA PUBLIC SERVICE COMPANY | Other postretirement benefits
Contributions
Employer's contributions under the plan		$ 1,000,000	$ 1,000,000	$ 14,000,000