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Regulatory Plant Decommissioning Recovery (Details) - USD ($) $ in Millions | Dec. 31, 2023 | Dec. 31, 2022 | Dec. 31, 2021
--- | --- | --- | ---
Regulatory Basis to GAAP Basis Reconciliation [Abstract] |  |  |
Asset Retirement Obligation | $ 3,218 | $ 3,380 | $ 3,151
Nuclear Plant [Member] |  |  |
Regulatory Basis to GAAP Basis Reconciliation [Abstract] |  |  |
Asset Retirement Obligation | 2,107 | 2,160 | $ 2,056
Estimate of Fair Value Measurement [Member] | Fair Value, Recurring [Member] |  |  |
Funded Status of Nuclear Decommissioning Obligation [Abstract] |  |  |
Decommissioning fund investments | $ 3,211 | 2,882 |
NSP Minnesota |  |  |
Regulatory Plant Decommissioning Recovery [Abstract] |  |  |
Percentage Of Total Obligation For Decommissioning Expected To Be Funded By External Funds | 100.00% |  |
NSP Minnesota | Estimate of Fair Value Measurement [Member] | Fair Value, Recurring [Member] |  |  |
Funded Status of Nuclear Decommissioning Obligation [Abstract] |  |  |
Decommissioning fund investments | $ 3,200 | $ 2,900 |

X
- 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/disclosureRef -Topic 410 -SubTopic 20 -Name Accounting Standards Codification -Section 25 -Paragraph 4 -Publisher FASB -URI https://asc.fasb.org//1943274/2147481999/410-20-25-4 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 410 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (c) -Publisher FASB -URI https://asc.fasb.org//1943274/2147481850/410-20-50-1 + Details
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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://www.xbrl.org/2009/role/commonPracticeRef -Topic 410 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org//1943274/2147481850/410-20-50-1 + 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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