XML 57 R47.htm IDEA: XBRL DOCUMENT v3.22.2
Regulatory Matters - Narrative (Details) - Minnesota Rate Case - MPUC - USD ($)
$ in Millions
 1 Months Ended 3 Months Ended
Dec. 03, 2020
Feb. 28, 2022
Jun. 30, 2022
Schedule of Regulatory Assets and Liabilities [Line Items]      
Revenue, approved rate increase, amount $ 6.9   $ 4.1
Revenue, approved rate increase, percent 3.20%    
Revenue requirement amount   $ 209.0  
Approved return on base rate, percent   7.18%  
Approved return on equity, percent   9.48%  
Approved equity ratio, percent   52.50%  
Recovery period   5 years  
Approved cap of annual base revenues, percent   4.00%