Nuclear Fuel Disposal (Details) - NSP Minnesota	Dec. 31, 2022 Canister
Monticello [Member]
Loss Contingencies [Line Items]
Number Of Authorized Canisters Filled And Placed In Dry Cask Nuclear Storage Facility	30
Prairie Island [Member]
Loss Contingencies [Line Items]
Number Of Authorized Canisters Filled And Placed In Dry Cask Nuclear Storage Facility	50
Number Of Authorized Canisters In Dry Cask Nuclear Storage Facility	64