Nuclear Insurance (Details) - NSP Minnesota - Nuclear Insurance $ in Millions	12 Months Ended
	Dec. 31, 2024 USD ($) Reactor
Nuclear Insurance [Abstract]
Nuclear insurance coverage secured for the Company's public liability exposure	$ 500
Nuclear insurance coverage exposure funded by the Secondary Financial Protection Program	15,800
Maximum assessments per reactor per accident	$ 166
Number of owned and licensed reactors | Reactor	3
Maximum funding requirement per reactor for any one year	$ 25
Maximum assessments for business interruption insurance each calendar year	19
Maximum assessment for property damage insurance NSP-Minnesota is subject to each calendar year	34
Maximum
Nuclear Insurance [Abstract]
Loss Contingency, Estimate of Possible Loss	16,300
Insurance coverage limits for NSP-Minnesota's nuclear plant sites	2,800
Business Interruption Insurance Coverage Provided by NEIL	490
Business Interruption Insurance Coverage Provided by NEIL - Prairie Island	$ 420