Commitments and Contingencies, Joint Operating System (Details) $ in Millions	12 Months Ended
Dec. 31, 2024 USD ($) Counterparty Reactor
Joint Operating System [Abstract]
Number of companies covered by FERC approved Interchange Agreement \| Counterparty	2
NSP-Minnesota \| Nuclear Insurance
Joint Operating System [Abstract]
Nuclear insurance coverage secured for the Company's public liability exposure	$ 500.0
Nuclear insurance coverage exposure funded by the Secondary Financial Protection Program	15,800.0
Maximum assessments per reactor per accident	$ 166.0
Number of owned and licensed reactors \| Reactor	3
Maximum funding requirement per reactor for any one year	$ 25.0
Maximum assessments for business interruption insurance each calendar year	19.0
Maximum assessment for property damage insurance NSP-Minnesota is subject to each calendar year	34.0
NSP-Minnesota \| Maximum \| Nuclear Insurance
Joint Operating System [Abstract]
Maximum possible loss contingency	16,300.0
Insurance coverage limits for NSP-Minnesota's nuclear plant sites	2,800.0
Business Interruption Insurance Coverage Provided by NEIL	490.0
Business Interruption Insurance Coverage Provided by NEIL - Prairie Island	$ 420.0

Business Interruption Insurance Coverage Provided by NEIL - Monticello

No definition available.

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- Definition

Business Interruption Insurance Coverage Provided by NEIL - Prairie Island

+ References

No definition available.

+ Details

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- Definition

Insurance coverage limits for property damage and site decontamination cleanup costs for each of the nuclear plant sites.

+ References

No definition available.

+ Details

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- Definition

-- None. No documentation exists for this element. --

+ References

No definition available.

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- Definition

The maximum assessments for business interruption insurance per calendar year if losses exceed accumulated reserve funds.

+ References

No definition available.

+ Details

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- Definition

The maximum assessment for property damage insurance per calendar year if losses exceed accumulated reserve funds.

+ References

No definition available.

+ Details

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- Definition

The maximum assessment the company is subject to for each reactor per accident incurred at any licensed nuclear facility within the United States, collected in annual installments.

+ References

No definition available.

+ Details

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- Definition

The annual maximum installment payment the company is subject to until either the maximum assessment has been reached or the claim has been met.

+ References

No definition available.

+ Details

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- Definition

The amount of coverage secured for the public liability exposure thru the Secondary Financial Protection Program, available from assessments by the federal government in case of a nuclear accident.

+ References

No definition available.

+ Details

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- Definition

The amount of coverage secured for the public liability exposure thru a pool of insurance companies.

+ References

No definition available.

+ Details

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- Definition

The number of companies covered by a FERC approved Interchange Agreement which provides for the sharing of all costs of generation and transmission facilities of the NSP System, including capital costs.

+ References

No definition available.

+ Details

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- Definition

The number of owned and licensed reactors.

+ References

No definition available.

+ Details

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- Definition

Reflects the estimated amount of loss from the specified contingency as of the balance sheet date.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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Reference 3: http://www.xbrl.org/2003/role/disclosureRef
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Reference 4: http://www.xbrl.org/2003/role/disclosureRef
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Reference 5: http://www.xbrl.org/2003/role/disclosureRef
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Reference 6: http://www.xbrl.org/2003/role/disclosureRef
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