XML 44 R31.htm IDEA: XBRL DOCUMENT
v3.6.0.2

Asset Retirement Obligations (Policies) | 12 Months Ended
--- | ---
Dec. 31, 2016
Asset Retirement Obligation Disclosure [Abstract] |
Asset Retirement Obligations, Policy [Policy Text Block] | An ARO is recognized in the period in which the legal obligation is incurred, and when the fair value of the liability can be reasonably estimated. Due to the long lead time involved until decommissioning activities occur, the Company uses present value techniques because quoted market prices and a market-risk premium are not available. The present value of estimated future dismantlement and restoration costs is capitalized and included in Electric utility plant, net on the consolidated balance sheets with a corresponding offset to ARO. Such estimates are revised periodically, with actual expenditures charged to the ARO as incurred. The estimated capitalized costs of AROs are depreciated over the estimated life of the related asset, which is included in Depreciation and amortization in the consolidated statements of income. Pursuant to regulation, the amortization of utility plant AROs is included in depreciation expense and in customer prices. Any differences in the timing of recognition of costs for financial reporting and ratemaking purposes are deferred as a regulatory asset or regulatory liability.

X
- References No definition available. + Details
Name: | us-gaap_AssetRetirementObligationDisclosureAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Disclosure of accounting policy for determining amounts to accrue and charge against earnings so as to satisfy legal obligations associated with the retirement (through sale, abandonment, recycling, or disposal in some other manner) of a tangible long-lived asset that result from the acquisition, construction, or development and (or) the normal operation of a long-lived asset. This accounting policy disclosure excludes obligations arising 1) in connection with leased property, whether imposed by a lease agreement or by a party other than the lessor, that meet the definition of either minimum lease payments or contingent rentals; 2) solely from a plan to sell or otherwise dispose of a long-lived asset and 3) from certain environmental remediation liabilities. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 410 -SubTopic 20 -Section 50 -Paragraph 1 -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 235 -SubTopic 10 -Section 50 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=68058157&loc=d3e18780-107790 + Details
Name: | us-gaap_AssetRetirementObligationsPolicy
Namespace Prefix: | us-gaap_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration