Commitments and Contingencies - Environmental Matters and Financial Assurances (Details) (USD $)	9 Months Ended	0 Months Ended		9 Months Ended
	Sep. 30, 2014 Arizona Public Service Company Four Corners Units 4 and 5	May 23, 2013 Four Corners New Mexico Tax Matter	May 23, 2013 Four Corners Arizona Public Service Company New Mexico Tax Matter	Sep. 30, 2014 Navajo Plant Arizona Public Service Company	Sep. 30, 2014 Cholla Arizona Public Service Company	Sep. 30, 2014 Cholla Units 2 And 3 Arizona Public Service Company	Sep. 30, 2014 Letter of Credit Arizona Public Service Company	Sep. 30, 2014 Equity Lessors in Palo Verde sale leaseback transactions Arizona Public Service Company	Sep. 30, 2014 Natural gas tolling contract obligations Arizona Public Service Company	Sep. 30, 2014 Letters of Credit Expiring in 2015 Arizona Public Service Company Letter_of_credit	Sep. 30, 2014 Letters of Credit Expiring in 2016 Arizona Public Service Company Letter_of_credit
Environmental Matters
Expected environmental cost	$ 350,000,000			$ 200,000,000	$ 200,000,000	$ 130,000,000
Percentage of share of cost of control	63.00%
Coal severance surtax, penalty, and interest		30,000,000
Share of the assessment			12,000,000
Financial Assurances
Outstanding letters of credit							$ 76,000,000	$ 23,000,000	$ 5,000,000
Number of letters of credit expiring										1	2