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Asset Retirement Obligations (Details) $ in Millions | 3 Months Ended
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Dec. 31, 2015 USD ($)
Asset Retirement Obligations |  |
Asset retirement obligations, period increase (decrease) | $ (8) |
Decommissioning study update - ARO nuclear | 5 years |
Accretion expense | $ 36 |
Balance at September 30, 2015 | 3,843 | [1]
Settlements | (22) | [1]
Asset Retirement Obligation, Revision of Estimate | (7) | [1]
Accretion (recorded as regulatory asset) | 37 | [1]
Balance at December 31, 2015 | 3,851 | [1]
Current portion of ARO | 183 |
Nuclear |  |
Asset Retirement Obligations |  |
Balance at September 30, 2015 | 2,187 | [1]
Settlements | 0 | [1]
Asset Retirement Obligation, Revision of Estimate | 0 | [1]
Accretion (recorded as regulatory asset) | 26 | [1]
Balance at December 31, 2015 | 2,213 | [1]
Non-nuclear |  |
Asset Retirement Obligations |  |
Balance at September 30, 2015 | 1,656 | [1]
Settlements | (22) | [1]
Asset Retirement Obligation, Revision of Estimate | (7) | [1]
Accretion (recorded as regulatory asset) | 11 | [1]
Balance at December 31, 2015 | $ 1,638 | [1]
[1] | The current portion of ARO in the amount of $183 million is included in Accounts payable and accrued liabilities at December 31, 2015.

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- Definition The maximum number of years in between ARO-nuclear decommissioning study updates. + References No definition available. + Details
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- Definition The amount of accretion recorded as a regulatory asset during the period. + References No definition available. + Details
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- Definition Amount of the Increase of Decrease in the amount of the asset retirement obligation as a result of the EPA ruling during the current period for changes in the amount or timing of the estimated cash flows associated with the settlement of the obligation. + References No definition available. + Details
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- Definition Reconciliation of Asset Retirement Obligations [Line Items] + References No definition available. + Details
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- Definition Amount of accretion expense, which includes, but is not limited to, accretion expense from asset retirement obligations, environmental remediation obligations, and other contingencies. + References No definition available. + Details
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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 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. + 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 + Details
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- Definition Amount of asset retirement obligations settled, or otherwise disposed of, during the period. This may include asset retirement obligations transferred to third parties associated with the sale of a long-lived asset. + 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)(2) -URI http://asc.fasb.org/extlink&oid=6392692&loc=d3e7535-110849 + Details
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- Definition Net Increase or Decrease in the asset retirement obligation during the period. + 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 + Details
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