XML 47 R33.htm IDEA: XBRL DOCUMENT v3.10.0.1
REGULATORY MATTERS - Schedule of Regulatory Assets and Liabilities (Details) - USD ($)
$ in Millions
Jun. 30, 2018
Sep. 30, 2017
Jun. 30, 2017
Regulatory Assets [Line Items]      
Regulatory Assets: Non-current $ 695.1 $ 791.1 $ 840.5
Total Regulatory Assets 791.8 966.6 985.1
Regulatory Liabilities [Line Items]      
Regulatory Liabilities: Non-current 364.3 157.2 139.8
Total Regulatory Liabilities 388.8 179.8 165.7
Rate Stabilization and Equalization (RSE) adjustment      
Regulatory Liabilities [Line Items]      
Regulatory Liabilities: Current 0.0 1.4 1.2
Unbilled service margin      
Regulatory Liabilities [Line Items]      
Regulatory Liabilities: Current 0.0 0.0 6.0
Deferred taxes due to customers      
Regulatory Liabilities [Line Items]      
Regulatory Liabilities: Non-current 182.7 0.0 0.0
Pension and postretirement benefit costs      
Regulatory Liabilities [Line Items]      
Regulatory Liabilities: Non-current 30.2 32.2 27.0
Refundable negative salvage      
Regulatory Liabilities [Line Items]      
Regulatory Liabilities: Current 5.2 8.2 8.2
Regulatory Liabilities: Non-current 0.0 4.1 4.1
Accrued cost of removal      
Regulatory Liabilities [Line Items]      
Regulatory Liabilities: Non-current 65.0 83.8 74.6
Unamortized purchased gas adjustments      
Regulatory Liabilities [Line Items]      
Regulatory Liabilities: Current 1.1 1.0 1.0
Regulatory Liabilities: Non-current 37.0 1.9 3.0
Other      
Regulatory Liabilities [Line Items]      
Regulatory Liabilities: Current 18.2 12.0 9.5
Regulatory Liabilities: Non-current 49.4 35.2 31.1
Total Regulatory Liabilities (current)      
Regulatory Liabilities [Line Items]      
Regulatory Liabilities: Current 24.5 22.6 25.9
Total Regulatory Liabilities (non-current)      
Regulatory Liabilities [Line Items]      
Regulatory Liabilities: Non-current 364.3 157.2 139.8
Future income taxes due from customers      
Regulatory Assets [Line Items]      
Regulatory Assets: Non-current 130.5 170.5 166.6
Pension and postretirement benefit costs      
Regulatory Assets [Line Items]      
Regulatory Assets: Current 43.2 42.2 41.7
Regulatory Assets: Non-current 369.4 404.7 453.4
Accrued cost of removal      
Regulatory Assets [Line Items]      
Regulatory Assets: Non-current 126.2 123.3 135.4
Unamortized purchased gas adjustments      
Regulatory Assets [Line Items]      
Regulatory Assets: Current 14.6 102.6 73.9
Regulatory Assets: Non-current 0.0 9.9 13.9
Energy efficiency      
Regulatory Assets [Line Items]      
Regulatory Assets: Non-current 31.8 29.0 27.8
Other      
Regulatory Assets [Line Items]      
Regulatory Assets: Current 38.9 30.7 29.0
Regulatory Assets: Non-current 37.2 53.7 43.4
Total Current Regulatory Assets      
Regulatory Assets [Line Items]      
Regulatory Assets: Current 96.7 175.5 144.6
Total Noncurrent Regulatory Assets      
Regulatory Assets [Line Items]      
Regulatory Assets: Non-current 695.1 791.1 840.5
Spire Missouri      
Regulatory Assets [Line Items]      
Regulatory Assets: Non-current 473.8 557.8 583.4
Total Regulatory Assets 528.9 653.4 650.6
Regulatory Liabilities [Line Items]      
Regulatory Liabilities: Non-current 281.6 81.2 83.6
Total Regulatory Liabilities 290.3 83.9 86.3
Spire Missouri | Deferred taxes due to customers      
Regulatory Liabilities [Line Items]      
Regulatory Liabilities: Non-current 164.6 0.0 0.0
Spire Missouri | Accrued cost of removal      
Regulatory Liabilities [Line Items]      
Regulatory Liabilities: Non-current 42.2 54.5 54.8
Spire Missouri | Unamortized purchased gas adjustments      
Regulatory Liabilities [Line Items]      
Regulatory Liabilities: Non-current 37.0 1.9 3.0
Spire Missouri | Other      
Regulatory Liabilities [Line Items]      
Regulatory Liabilities: Current 8.7 2.7 2.7
Regulatory Liabilities: Non-current 37.8 24.8 25.8
Spire Missouri | Total Regulatory Liabilities (current)      
Regulatory Liabilities [Line Items]      
Regulatory Liabilities: Current 8.7 2.7 2.7
Spire Missouri | Total Regulatory Liabilities (non-current)      
Regulatory Liabilities [Line Items]      
Regulatory Liabilities: Non-current 281.6 81.2 83.6
Spire Missouri | Future income taxes due from customers      
Regulatory Assets [Line Items]      
Regulatory Assets: Non-current 128.4 170.5 166.6
Spire Missouri | Pension and postretirement benefit costs      
Regulatory Assets [Line Items]      
Regulatory Assets: Current 34.9 34.9 34.9
Regulatory Assets: Non-current 297.2 322.7 352.3
Spire Missouri | Unamortized purchased gas adjustments      
Regulatory Assets [Line Items]      
Regulatory Assets: Current 7.0 57.4 29.0
Regulatory Assets: Non-current 0.0 9.9 13.9
Spire Missouri | Energy efficiency      
Regulatory Assets [Line Items]      
Regulatory Assets: Non-current 31.8 29.0 27.8
Spire Missouri | Other      
Regulatory Assets [Line Items]      
Regulatory Assets: Current 13.2 3.3 3.3
Regulatory Assets: Non-current 16.4 25.7 22.8
Spire Missouri | Total Current Regulatory Assets      
Regulatory Assets [Line Items]      
Regulatory Assets: Current 55.1 95.6 67.2
Spire Missouri | Total Noncurrent Regulatory Assets      
Regulatory Assets [Line Items]      
Regulatory Assets: Non-current 473.8 557.8 583.4
Spire Alabama      
Regulatory Assets [Line Items]      
Regulatory Assets: Non-current 193.4 197.0 228.7
Total Regulatory Assets 220.3 261.6 290.9
Regulatory Liabilities [Line Items]      
Regulatory Liabilities: Non-current 33.7 39.6 34.4
Total Regulatory Liabilities 42.5 51.6 52.2
Spire Alabama | Rate Stabilization and Equalization (RSE) adjustment      
Regulatory Liabilities [Line Items]      
Regulatory Liabilities: Current 0.0 1.4 1.2
Spire Alabama | Unbilled service margin      
Regulatory Liabilities [Line Items]      
Regulatory Liabilities: Current 0.0 0.0 6.0
Spire Alabama | Pension and postretirement benefit costs      
Regulatory Liabilities [Line Items]      
Regulatory Liabilities: Non-current 30.2 32.2 27.0
Spire Alabama | Refundable negative salvage      
Regulatory Liabilities [Line Items]      
Regulatory Liabilities: Current 5.2 8.2 8.2
Regulatory Liabilities: Non-current 0.0 4.1 4.1
Spire Alabama | Other      
Regulatory Liabilities [Line Items]      
Regulatory Liabilities: Current 3.6 2.4 2.4
Regulatory Liabilities: Non-current 3.5 3.3 3.3
Spire Alabama | Total Regulatory Liabilities (current)      
Regulatory Liabilities [Line Items]      
Regulatory Liabilities: Current 8.8 12.0 17.8
Spire Alabama | Total Regulatory Liabilities (non-current)      
Regulatory Liabilities [Line Items]      
Regulatory Liabilities: Non-current 33.7 39.6 34.4
Spire Alabama | Pension and postretirement benefit costs      
Regulatory Assets [Line Items]      
Regulatory Assets: Current 7.3 7.2 6.8
Regulatory Assets: Non-current 64.5 72.6 92.2
Spire Alabama | Accrued cost of removal      
Regulatory Assets [Line Items]      
Regulatory Assets: Non-current 126.2 123.3 135.4
Spire Alabama | Unamortized purchased gas adjustments      
Regulatory Assets [Line Items]      
Regulatory Assets: Current 7.6 45.2 44.9
Spire Alabama | Other      
Regulatory Assets [Line Items]      
Regulatory Assets: Current 12.0 12.2 10.5
Regulatory Assets: Non-current 2.7 1.1 1.1
Spire Alabama | Total Current Regulatory Assets      
Regulatory Assets [Line Items]      
Regulatory Assets: Current 26.9 64.6 62.2
Spire Alabama | Total Noncurrent Regulatory Assets      
Regulatory Assets [Line Items]      
Regulatory Assets: Non-current $ 193.4 $ 197.0 $ 228.7