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Retirement Plans and Other Benefits Retirement Plans and Other Benefits (Details) | 1 Months Ended | 12 Months Ended |
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Jul. 31, 2012 | Dec. 31, 2016 USD ($) | Dec. 31, 2015 USD ($) | Dec. 31, 2014 USD ($) | Dec. 31, 2013 USD ($) | Dec. 31, 2012 USD ($) | Dec. 31, 2011 USD ($) | Jan. 01, 2015 Age
Plan Design Changes [Abstract] |  |  |  |  |  |  |  |
Noncurrent asset |  | $ 166,206,000 | $ 185,997,000 |  |  |  |  |
Amount of other postretirement benefit trust assets for union employee medical costs |  | 140,000,000 |  |  |  |  |  |
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 |  | 54,000,000 |  |  |  |  |  |
Pension Benefits |  |  |  |  |  |  |  |
Plan Design Changes [Abstract] |  |  |  |  |  |  |  |
Noncurrent asset |  | $ 0 | 0 |  |  |  |  |
Expected long-term return on plan assets for next fiscal year (as a percent) |  | 6.55% |  |  |  |  |  |
Contributions |  |  |  |  |  |  |  |
Employer's contributions under the plan |  | $ 100,000,000 | 100,000,000 | 175,000,000 |  |  |  |
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) |  | 57.00% |  |  |  |  |  |
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) |  | 43.00% |  |  |  |  |  |
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 |  |  |  |
Noncurrent asset |  | $ 166,206,000 | 185,997,000 |  |  |  |  |
Expected long-term return on plan assets for next fiscal year (as a percent) |  | 6.37% |  |  |  |  |  |
Contributions |  |  |  |  |  |  |  |
Employer's contributions under the plan |  | $ 819,000 | 791,000 | 1,000,000 |  |  |  |
Expected employer contributions |  |  |  |  |  |  |  |
2017 (less than) |  | 1,000,000 |  |  |  |  |  |
2018 (less than) |  | 1,000,000 |  |  |  |  |  |
2019 (less than) |  | $ 1,000,000 |  |  |  |  |  |
Other postretirement benefits | Fixed income |  |  |  |  |  |  |  |
Target asset allocation |  |  |  |  |  |  |  |
Actual asset allocation (as a percent) |  | 51.00% |  |  |  |  |  |
Other postretirement benefits | Non-fixed income |  |  |  |  |  |  |  |
Target asset allocation |  |  |  |  |  |  |  |
Actual asset allocation (as a percent) |  | 49.00% |  |  |  |  |  |
Pinnacle West |  |  |  |  |  |  |  |
Employee savings plan benefits |  |  |  |  |  |  |  |
Expenses recorded for the defined contribution savings plan |  | $ 10,000,000 | 9,000,000 | 9,000,000 |  |  |  |
ARIZONA PUBLIC SERVICE COMPANY |  |  |  |  |  |  |  |
Plan Design Changes [Abstract] |  |  |  |  |  |  |  |
Noncurrent asset |  | $ 162,911,000 | 182,625,000 |  |  |  |  |
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 | 100,000,000 | 175,000,000 |  |  |  |
ARIZONA PUBLIC SERVICE COMPANY | Other postretirement benefits |  |  |  |  |  |  |  |
Contributions |  |  |  |  |  |  |  |
Employer's contributions under the plan |  | $ 1,000,000 | $ 1,000,000 | $ 1,000,000 |  |  |  |

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