Retirement Plans and Other Benefits Retirement Plans and Other Benefits (Details) (USD $)	1 Months Ended	12 Months Ended
	Jul. 31, 2012	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Jan. 01, 2015 Age
Plan Design Changes [Abstract]
Assets for other postretirement benefits		$ 152,290,000	$ 0
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		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, maximum contribution amount		75,000,000
Partnership funding commitments, funded amount		30,000,000
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		175,000,000	140,500,000	65,000,000
Minimum contributions under MAP-21
Minimum contributions under MAP-21		0
Expected employer contributions
Expected employer contributions		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)		61.00%
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)		39.00%
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]
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		152,290,000	0
Regulatory liabilities		231,000,000
Expected long-term return on plan assets for next fiscal year (as a percent)		4.74%
Contributions
Employer's contributions under the plan		770,000	14,438,000	22,707,000
Expected employer contributions
2015		1,000,000
2016		100,000,000
2017		100,000,000
Other postretirement benefits | Fixed income
Target asset allocation
Actual asset allocation (as a percent)		43.00%
Other postretirement benefits | Non-fixed income
Target asset allocation
Actual asset allocation (as a percent)		57.00%
Maximum | Pension Benefits
Expected employer contributions
2015		100,000,000
2016		100,000,000
2017		100,000,000
Subsequent event | Other postretirement benefits
Plan Design Changes [Abstract]
Age eligible for benefit						65
Pinnacle West
Employee savings plan benefits
Expenses recorded for the defined contribution savings plan		9,000,000	9,000,000	8,000,000
ARIZONA PUBLIC SERVICE COMPANY
Plan Design Changes [Abstract]
Assets for other postretirement benefits		149,260,000	0
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		175,000,000	140,000,000	64,000,000
ARIZONA PUBLIC SERVICE COMPANY | Other postretirement benefits
Contributions
Employer's contributions under the plan		$ 1,000,000	$ 14,000,000	$ 22,000,000