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Commitments and Contingencies, Removal Costs (Details) - USD ($) $ in Millions | Dec. 31, 2018 | Dec. 31, 2017
--- | --- | ---
Regulatory Liabilities [Line Items] |  |
Decommissioning Fund Investments, Fair Value | $ 2,055 |
Percentage Of Total Obligation For Decommissioning Expected To Be Funded By External Funds | 100.00% |
Plant Removal Costs |  |
Regulatory Liabilities [Line Items] |  |
Regulatory liabilities | $ 1,175 | $ 1,131
Plant Removal Costs | NSP-Minnesota |  |
Regulatory Liabilities [Line Items] |  |
Regulatory liabilities | 485 | 442
Plant Removal Costs | PSCo |  |
Regulatory Liabilities [Line Items] |  |
Regulatory liabilities | 344 | 346
Plant Removal Costs | SPS |  |
Regulatory Liabilities [Line Items] |  |
Regulatory liabilities | 188 | 197
Plant Removal Costs | NSP-Wisconsin |  |
Regulatory Liabilities [Line Items] |  |
Regulatory liabilities | $ 158 | $ 146

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- Definition The fair value of investments held in a trust fund to pay for the costs of decontaminating and decommissioning facilities, whether such amount is presented as a separate caption or as a parenthetical disclosure on the balance sheet. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 410 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=6392692&loc=d3e7535-110849 + 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://fasb.org/us-gaap/role/ref/legacyRef -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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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
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- Definition Percentage of total obligation for decommissioning nuclear facilities expected to be funded by external decommissioning trust fund. + References No definition available. + Details
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- Details
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