Commitments and Contingencies Commitments and Contingencies - Environmental Matters and Financial Assurances (Details)			9 Months Ended	12 Months Ended
	Aug. 17, 2015 USD ($) power_plant	May. 23, 2013 USD ($)	Sep. 30, 2015 USD ($)	Dec. 31, 2015 USD ($)
Environmental Matters [Abstract]
Clean power plan, optional extension period				2 years
Four Corners | ARIZONA PUBLIC SERVICE COMPANY
Environmental Matters [Abstract]
Additional expected environment cost				$ 15,000,000
Cholla | ARIZONA PUBLIC SERVICE COMPANY
Environmental Matters [Abstract]
Additional expected environment cost				85,000,000
Cholla Units 1-3 | ARIZONA PUBLIC SERVICE COMPANY
Environmental Matters [Abstract]
Expected environmental cost				8,000,000
Clean Air Act Citizen Lawsuit | ARIZONA PUBLIC SERVICE COMPANY
Commitments and Contingencies [Line Items]
Loss contingency, number of units | power_plant	2
Clean Air Act Citizen Lawsuit | Four Corners
Commitments and Contingencies [Line Items]
Loss contingency, civil penalty amount	$ 1,500,000
New Mexico Tax Matter | Four Corners
Environmental Matters [Abstract]
Coal severance surtax, penalty, and interest		$ 30,000,000
New Mexico Tax Matter | Four Corners | ARIZONA PUBLIC SERVICE COMPANY
Environmental Matters [Abstract]
Share of the assessment		$ 12,000,000
Letter of credit | ARIZONA PUBLIC SERVICE COMPANY
Financial Assurances
Outstanding letters of credit				79,000,000
Equity Lessors Sale Leaseback Letter of Credit | ARIZONA PUBLIC SERVICE COMPANY
Financial Assurances
Outstanding letters of credit				158,000,000
Natural Gas Tolling Letter of Credit | ARIZONA PUBLIC SERVICE COMPANY
Financial Assurances
Outstanding letters of credit				6,700,000
Four Corners Units 4 and 5 | Four Corners | ARIZONA PUBLIC SERVICE COMPANY
Environmental Matters [Abstract]
Additional expected environment cost				45,000,000
Four Corners Units 4 and 5 | Navajo Plant | ARIZONA PUBLIC SERVICE COMPANY
Environmental Matters [Abstract]
Expected environmental cost				$ 200,000,000
Four Corners Units 4 and 5 | Natural Gas Tolling Letter of Credit | ARIZONA PUBLIC SERVICE COMPANY
Environmental Matters [Abstract]
Percentage of share of cost of control				63.00%
Additional percentage share of cost of control				7.00%
Minimum | Four Corners Units 4 and 5 | Four Corners | ARIZONA PUBLIC SERVICE COMPANY
Environmental Matters [Abstract]
Expected environmental cost				$ 400,000,000
Regional Haze Rules | Cholla | ARIZONA PUBLIC SERVICE COMPANY
Environmental Matters [Abstract]
Expected environmental cost			$ 100,000,000
Mercury and Air Toxic Standards | Navajo Generating Station | ARIZONA PUBLIC SERVICE COMPANY
Environmental Matters [Abstract]
Expected environmental cost				1,000,000
Coal Combustion Waste | Navajo Generating Station | ARIZONA PUBLIC SERVICE COMPANY
Environmental Matters [Abstract]
Additional expected environment cost				$ 1,000,000