Asset Retirement Obligations - Narrative (Details) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2016 USD ($)	Sep. 30, 2016 USD ($) turbine_unit	Dec. 31, 2015 USD ($)
Asset Retirement Obligations
Asset retirement obligation, current	$ 11,852	$ 11,852	$ 28,573
Arizona Public Service Company
Asset Retirement Obligations
Newly incurred liabilities	9,000	18,927
Asset retirement obligation, current	11,505	11,505	28,573
Asset retirement obligation	$ 470,480	$ 470,480	$ 443,576
Arizona Public Service Company \| Ocotillo Steam Units
Asset Retirement Obligations
Number of constructed turbine units \| turbine_unit		5
Newly incurred liabilities		$ 10,000

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- Definition

Property, Plant and Equipment, Number of Constructed Turbine Units

+ References

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- Definition

The carrying amount of a liability for an asset retirement obligation. An asset retirement obligation is a legal obligation associated with the disposal or retirement of a tangible long-lived asset that results from the acquisition, construction or development, or the normal operations of a long-lived asset, except for certain obligations of lessees.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 410
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=6392692&loc=d3e7535-110849

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Asset Retirement Obligation
-URI http://asc.fasb.org/extlink&oid=6505190

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- Definition

Current portion of the carrying amount of a liability for an asset retirement obligation. An asset retirement obligation is a legal obligation associated with the disposal or retirement of a tangible long-lived asset that results from the acquisition, construction or development, or the normal operations of a long-lived asset, except for certain obligations of lessees.

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- Definition

Amount of asset retirement obligations incurred during the period.

+ References

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