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Asset Retirement Obligations (Details) $ in Thousands | 12 Months Ended
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Dec. 31, 2016 USD ($) turbine_unit | Dec. 31, 2015 USD ($)
Changes attributable to: |  |
Asset retirement obligations, current | $ 9,135 | $ 28,573
ARIZONA PUBLIC SERVICE COMPANY |  |
Change in asset retirement obligations |  |
Asset retirement obligations at the beginning of year | 443,576 | 390,750
Changes attributable to: |  |
Accretion expense | 26,656 | 25,163
Settlements | (15,732) | (32,048)
Estimated cash flow revisions | 151,046 | 17,556
Newly incurred or acquired obligations | 18,929 | 42,155
Asset retirement obligations at the end of year | 624,475 | 443,576
Asset retirement obligations, current | $ 8,703 | 28,573
Ocotillo Steam Units | ARIZONA PUBLIC SERVICE COMPANY |  |
Asset Retirement Obligations |  |
Number of constructed turbine units | turbine_unit | 5 |
Changes attributable to: |  |
Newly incurred or acquired obligations | $ 10,000 |
El Paso's Share of Four Corners Units 4 & 5 [Member] | 4CA |  |
Changes attributable to: |  |
Newly incurred or acquired obligations | 9,000 |
Four Corners | ARIZONA PUBLIC SERVICE COMPANY |  |
Changes attributable to: |  |
Settlements | (16,000) | (32,000)
Estimated cash flow revisions |  | 24,000
Palo Verde Nuclear Generating Station | ARIZONA PUBLIC SERVICE COMPANY |  |
Asset Retirement Obligations |  |
Increase in plant services | 131,000 |
Decrease in regulatory liability | 20,000 |
Changes attributable to: |  |
Estimated cash flow revisions | $ 151,000 |
Cholla | ARIZONA PUBLIC SERVICE COMPANY |  |
Asset Retirement Obligations |  |
Increase in plant services |  | 23,000
Decrease in regulatory liability |  | 16,000
Changes attributable to: |  |
Estimated cash flow revisions |  | (3,000)
Newly incurred or acquired obligations |  | $ 39,000

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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 + Details
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- Definition Amount of accretion expense recognized during the period that is associated with an asset retirement obligation. Accretion expense measures and incorporates changes due to the passage of time into the carrying amount of the liability. + 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)(3) -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 -Topic 410 -SubTopic 20 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6392676&loc=d3e7480-110848 + Details
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