XML 52 R39.htm IDEA: XBRL DOCUMENT v3.24.2
Note 5 - Regulatory Matters (Details Textual) - USD ($)
$ in Millions
6 Months Ended 15 Months Ended
Apr. 16, 2024
Jan. 01, 2024
Dec. 14, 2023
Dec. 13, 2023
Oct. 04, 2023
Apr. 30, 2023
Apr. 20, 2023
Jan. 01, 2023
Aug. 31, 2024
Apr. 16, 2024
Jun. 30, 2024
Spire Missouri [Member] | Missouri Public Service Commission [Member] | Infrastructure System Replacement Surcharge [Member]                      
Public Utilities, Approved Rate Increase (Decrease), Amount $ 16.8       $ 12.4   $ 7.7     $ 36.9  
Public Utilities, Requested Rate Increase (Decrease), Amount                 $ 17.7    
Spire Alabama Inc [Member] | Alabama Public Service Commission [Member]                      
Annual Revenue Increase From Rates, Amount   $ 14.3           $ 15.0      
Spire Gulf [Member]                      
Annual Revenue Increase From Rates, Amount       $ 2.7              
Public Utilities, Approved Rate, Increase Decrease Annualized Revenue       $ 2.0   $ 1.8   2.5      
Spire Mississippi [Member]                      
Public Utilities, Approved Rate, Increase Decrease Annualized Revenue     $ 0.8         $ 0.8      
Future Income Taxes Due From Customers and Pension and Other Postretirement Benefit Costs [Member]                      
Remaining Recovery Period of Regulatory Assets for which No Return on Investment During Recovery Period is Provided (Year)                     20 years
PGA Assets [Member]                      
Remaining Recovery Period of Regulatory Assets for which No Return on Investment During Recovery Period is Provided (Year)                     2 years
PGA Assets Not Earning A Return [Member]                      
Remaining Recovery Period of Regulatory Assets for which No Return on Investment During Recovery Period is Provided (Year)                     15 years