Regulatory Plant Decommissioning Recovery (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Regulatory Basis to GAAP Basis Reconciliation [Abstract]
Asset Retirement Obligation	$ 3,380	$ 3,151	$ 2,884
Nuclear Plant [Member]
Regulatory Basis to GAAP Basis Reconciliation [Abstract]
Asset Retirement Obligation	2,160	2,056	$ 1,957
Estimate of Fair Value Measurement [Member] | Fair Value, Recurring [Member]
Funded Status of Nuclear Decommissioning Obligation [Abstract]
Decommissioning fund investments	$ 2,882	3,256
NSP Minnesota
Regulatory Plant Decommissioning Recovery [Abstract]
Percentage Of Total Obligation For Decommissioning Expected To Be Funded By External Funds	100.00%
NSP Minnesota | Nuclear Decommissioning Fund | Estimate of Fair Value Measurement [Member] | Fair Value, Recurring [Member]
Funded Status of Nuclear Decommissioning Obligation [Abstract]
Decommissioning fund investments	$ 2,900	$ 3,300