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Regulatory Assets and Liabilities Schedule of Regulatory Assets and Liabilities (Details) - USD ($) $ in Millions | 12 Months Ended |
--- | --- | ---
Dec. 31, 2016 | Dec. 31, 2015
Regulatory Assets [Line Items] |  |
Remaining Recovery Period of Regulatory Assets, Price Risk Management | 6 years |
Remaining Recovery Period of Regulatory Asset, Debt Reacquisition Costs | 6 years |
Price risk management | $ 18 | $ 10
Deferred income taxes | $ 29 | 42
Remaining refund period of regulatory liability, Trojan decommissioning activities | 3 years |
Current Regulatory Liabilities [Member] |  |
Regulatory Assets [Line Items] |  |
Asset retirement removal costs | $ 0 | 0
Proceeds from Legal Settlements | 18 | 17
Asset retirement obligations | 0 | 0
Other | 33 | 38
Total regulatory liabilities | 51 | 55
Noncurrent Regulatory Liabilities [Member] |  |
Regulatory Assets [Line Items] |  |
Asset retirement removal costs | 887 | 837
Proceeds from Legal Settlements | 0 | 15
Asset retirement obligations | 49 | 45
Other | 22 | 31
Total regulatory liabilities | 958 | 928
Regulatory Assets, Current [Member] |  |
Regulatory Assets [Line Items] |  |
Price risk management | 26 | 120
Pension and other postretirement plans | 0 | 0
Deferred income taxes | 0 | 0
Debt reacquisition costs | 0 | 0
Other | 10 | 9
Total regulatory assets | 36 | 129
Noncurrent Regulatory Assets [Member] |  |
Regulatory Assets [Line Items] |  |
Price risk management | 120 | 161
Pension and other postretirement plans | 235 | 239
Deferred income taxes | 86 | 86
Debt reacquisition costs | 22 | 16
Other | 35 | 22
Total regulatory assets | $ 498 | $ 524

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- Definition regulatory liabilities - Amounts held in trojan decommissioning trust that is to be returned to customers in future rate proceedings. + References No definition available. + Details
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- Definition Noncurrent 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, after accumulated amortization, of debt issuance costs. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 835 -SubTopic 30 -Section 45 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=64930785&loc=d3e28555-108399 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.17) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
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- Definition Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences derived regulatory assets and liabilities. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 8 -URI http://asc.fasb.org/extlink&oid=65882285&loc=d3e32632-109319 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 6 -URI http://asc.fasb.org/extlink&oid=65882285&loc=d3e32621-109319 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 25 -Paragraph 20 -URI http://asc.fasb.org/extlink&oid=68052875&loc=d3e28680-109314 + Details
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- Definition Net amount of other deferred costs capitalized at the end of the reporting period. Does not include deferred finance costs or deferred acquisition costs of insurance companies. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.17) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
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- Definition The amount for the individual regulatory asset as itemized in a table of regulatory assets as of the end of the period. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 980 -SubTopic 340 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6499975&loc=d3e44250-110382 + Details
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- Definition The amount for the individual regulatory liability as itemized in a table of regulatory liabilities as of the end of the period. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 980 -SubTopic 405 -Section 25 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6500807&loc=d3e48068-110394 + Details
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