OPERATING REVENUES - DISAGGREGATION OF OPERATING REVENUES BY SEGMENT (Details) - USD ($) $ in Millions | 3 Months Ended | 6 Months Ended |
Jun. 30, 2022 | Jun. 30, 2021 | Jun. 30, 2022 | Jun. 30, 2021 |
Disaggregation of Operating Revenues | | | | |
Total operating revenues | $ 2,127.9 | $ 1,676.2 | $ 5,036 | $ 4,367.6 |
Revenues from contracts with customers | | | | |
Disaggregation of Operating Revenues | | | | |
Revenues from contracts with customers | 2,121.2 | 1,654.3 | 5,020.8 | 4,323.3 |
Other operating revenues | | | | |
Disaggregation of Operating Revenues | | | | |
Other operating revenues | 6.7 | 21.9 | 15.2 | 44.3 |
Total regulated revenues | Revenues from contracts with customers | | | | |
Disaggregation of Operating Revenues | | | | |
Revenues from contracts with customers | 2,089.6 | 1,629.6 | 4,942.5 | 4,272.3 |
Electric | Revenues from contracts with customers | | | | |
Disaggregation of Operating Revenues | | | | |
Revenues from contracts with customers | 1,221.1 | 1,083.2 | 2,408.6 | 2,178.2 |
Natural gas | Revenues from contracts with customers | | | | |
Disaggregation of Operating Revenues | | | | |
Revenues from contracts with customers | 868.5 | 546.4 | 2,533.9 | 2,094.1 |
Other non-utility revenues | Revenues from contracts with customers | | | | |
Disaggregation of Operating Revenues | | | | |
Revenues from contracts with customers | 31.6 | 24.7 | 78.3 | 51 |
Reconciling Eliminations | | | | |
Disaggregation of Operating Revenues | | | | |
Total operating revenues | (115.5) | (112.5) | (232.4) | (227.2) |
Reconciling Eliminations | Revenues from contracts with customers | | | | |
Disaggregation of Operating Revenues | | | | |
Revenues from contracts with customers | (15) | (12.6) | (31.4) | (27.5) |
Reconciling Eliminations | Other operating revenues | | | | |
Disaggregation of Operating Revenues | | | | |
Other operating revenues | (100.5) | (99.9) | (201) | (199.7) |
Reconciling Eliminations | Total regulated revenues | Revenues from contracts with customers | | | | |
Disaggregation of Operating Revenues | | | | |
Revenues from contracts with customers | (11) | (8.7) | (25.8) | (22) |
Reconciling Eliminations | Electric | Revenues from contracts with customers | | | | |
Disaggregation of Operating Revenues | | | | |
Revenues from contracts with customers | 0 | 0 | 0 | 0 |
Reconciling Eliminations | Natural gas | Revenues from contracts with customers | | | | |
Disaggregation of Operating Revenues | | | | |
Revenues from contracts with customers | (11) | (8.7) | (25.8) | (22) |
Reconciling Eliminations | Other non-utility revenues | Revenues from contracts with customers | | | | |
Disaggregation of Operating Revenues | | | | |
Revenues from contracts with customers | (4) | (3.9) | (5.6) | (5.5) |
Total Utility Operations | | | | |
Disaggregation of Operating Revenues | | | | |
Total operating revenues | 2,099.7 | 1,655.1 | 4,965 | 4,323.5 |
Total Utility Operations | Other operating revenues | | | | |
Disaggregation of Operating Revenues | | | | |
Other operating revenues | 6.6 | 21.8 | 14.9 | 44.1 |
Total Utility Operations | Transferred over time | Revenues from contracts with customers | | | | |
Disaggregation of Operating Revenues | | | | |
Revenues from contracts with customers | 2,093.1 | 1,633.3 | 4,950.1 | 4,279.4 |
Total Utility Operations | Total regulated revenues | Transferred over time | Revenues from contracts with customers | | | | |
Disaggregation of Operating Revenues | | | | |
Revenues from contracts with customers | 2,088.6 | 1,628.9 | 4,941 | 4,270.3 |
Total Utility Operations | Electric | Transferred over time | Revenues from contracts with customers | | | | |
Disaggregation of Operating Revenues | | | | |
Revenues from contracts with customers | 1,221.1 | 1,083.2 | 2,408.6 | 2,178.2 |
Total Utility Operations | Natural gas | Transferred over time | Revenues from contracts with customers | | | | |
Disaggregation of Operating Revenues | | | | |
Revenues from contracts with customers | 867.5 | 545.7 | 2,532.4 | 2,092.1 |
Total Utility Operations | Other non-utility revenues | Transferred over time | Revenues from contracts with customers | | | | |
Disaggregation of Operating Revenues | | | | |
Revenues from contracts with customers | 4.5 | 4.4 | 9.1 | 9.1 |
Wisconsin | | | | |
Disaggregation of Operating Revenues | | | | |
Total operating revenues | 1,557.4 | 1,307.5 | 3,499.7 | 3,039.2 |
Wisconsin | Other operating revenues | | | | |
Disaggregation of Operating Revenues | | | | |
Other operating revenues | 6.8 | 11.6 | 14.8 | 21 |
Wisconsin | Transferred over time | Revenues from contracts with customers | | | | |
Disaggregation of Operating Revenues | | | | |
Revenues from contracts with customers | 1,550.6 | 1,295.9 | 3,484.9 | 3,018.2 |
Wisconsin | Total regulated revenues | Transferred over time | Revenues from contracts with customers | | | | |
Disaggregation of Operating Revenues | | | | |
Revenues from contracts with customers | 1,550.6 | 1,295.9 | 3,484.9 | 3,018.2 |
Wisconsin | Electric | Transferred over time | Revenues from contracts with customers | | | | |
Disaggregation of Operating Revenues | | | | |
Revenues from contracts with customers | 1,221.1 | 1,083.2 | 2,408.6 | 2,178.2 |
Wisconsin | Natural gas | Transferred over time | Revenues from contracts with customers | | | | |
Disaggregation of Operating Revenues | | | | |
Revenues from contracts with customers | 329.5 | 212.7 | 1,076.3 | 840 |
Wisconsin | Other non-utility revenues | Transferred over time | Revenues from contracts with customers | | | | |
Disaggregation of Operating Revenues | | | | |
Revenues from contracts with customers | 0 | 0 | 0 | 0 |
Illinois | | | | |
Disaggregation of Operating Revenues | | | | |
Total operating revenues | 442.4 | 275.5 | 1,124.5 | 978.9 |
Illinois | Other operating revenues | | | | |
Disaggregation of Operating Revenues | | | | |
Other operating revenues | 0.2 | 9.4 | 2.4 | 19.3 |
Illinois | Transferred over time | Revenues from contracts with customers | | | | |
Disaggregation of Operating Revenues | | | | |
Revenues from contracts with customers | 442.2 | 266.1 | 1,122.1 | 959.6 |
Illinois | Total regulated revenues | Transferred over time | Revenues from contracts with customers | | | | |
Disaggregation of Operating Revenues | | | | |
Revenues from contracts with customers | 442.2 | 266.1 | 1,122.1 | 959.6 |
Illinois | Electric | Transferred over time | Revenues from contracts with customers | | | | |
Disaggregation of Operating Revenues | | | | |
Revenues from contracts with customers | 0 | 0 | 0 | 0 |
Illinois | Natural gas | Transferred over time | Revenues from contracts with customers | | | | |
Disaggregation of Operating Revenues | | | | |
Revenues from contracts with customers | 442.2 | 266.1 | 1,122.1 | 959.6 |
Illinois | Other non-utility revenues | Transferred over time | Revenues from contracts with customers | | | | |
Disaggregation of Operating Revenues | | | | |
Revenues from contracts with customers | 0 | 0 | 0 | 0 |
Other States | | | | |
Disaggregation of Operating Revenues | | | | |
Total operating revenues | 99.9 | 72.1 | 340.8 | 305.4 |
Other States | Other operating revenues | | | | |
Disaggregation of Operating Revenues | | | | |
Other operating revenues | (0.4) | 0.8 | (2.3) | 3.8 |
Other States | Transferred over time | Revenues from contracts with customers | | | | |
Disaggregation of Operating Revenues | | | | |
Revenues from contracts with customers | 100.3 | 71.3 | 343.1 | 301.6 |
Other States | Total regulated revenues | Transferred over time | Revenues from contracts with customers | | | | |
Disaggregation of Operating Revenues | | | | |
Revenues from contracts with customers | 95.8 | 66.9 | 334 | 292.5 |
Other States | Electric | Transferred over time | Revenues from contracts with customers | | | | |
Disaggregation of Operating Revenues | | | | |
Revenues from contracts with customers | 0 | 0 | 0 | 0 |
Other States | Natural gas | Transferred over time | Revenues from contracts with customers | | | | |
Disaggregation of Operating Revenues | | | | |
Revenues from contracts with customers | 95.8 | 66.9 | 334 | 292.5 |
Other States | Other non-utility revenues | Transferred over time | Revenues from contracts with customers | | | | |
Disaggregation of Operating Revenues | | | | |
Revenues from contracts with customers | 4.5 | 4.4 | 9.1 | 9.1 |
Non-Utility Energy Infrastructure | | | | |
Disaggregation of Operating Revenues | | | | |
Total operating revenues | 143.6 | 133.5 | 303.1 | 271.1 |
Non-Utility Energy Infrastructure | Revenues from contracts with customers | | | | |
Disaggregation of Operating Revenues | | | | |
Revenues from contracts with customers | 43.1 | 33.6 | 102.1 | 71.4 |
Non-Utility Energy Infrastructure | Other operating revenues | | | | |
Disaggregation of Operating Revenues | | | | |
Other operating revenues | 100.5 | 99.9 | 201 | 199.7 |
Non-Utility Energy Infrastructure | Total regulated revenues | Revenues from contracts with customers | | | | |
Disaggregation of Operating Revenues | | | | |
Revenues from contracts with customers | 12 | 9.4 | 27.3 | 24 |
Non-Utility Energy Infrastructure | Electric | Revenues from contracts with customers | | | | |
Disaggregation of Operating Revenues | | | | |
Revenues from contracts with customers | 0 | 0 | | 0 |
Non-Utility Energy Infrastructure | Natural gas | Revenues from contracts with customers | | | | |
Disaggregation of Operating Revenues | | | | |
Revenues from contracts with customers | 12 | 9.4 | 27.3 | 24 |
Non-Utility Energy Infrastructure | Other non-utility revenues | Revenues from contracts with customers | | | | |
Disaggregation of Operating Revenues | | | | |
Revenues from contracts with customers | 31.1 | 24.2 | 74.8 | 47.4 |
Corporate and Other | | | | |
Disaggregation of Operating Revenues | | | | |
Total operating revenues | 0.1 | 0.1 | 0.3 | 0.2 |
Corporate and Other | Revenues from contracts with customers | | | | |
Disaggregation of Operating Revenues | | | | |
Revenues from contracts with customers | 0 | 0 | 0 | 0 |
Corporate and Other | Other operating revenues | | | | |
Disaggregation of Operating Revenues | | | | |
Other operating revenues | 0.1 | 0.1 | 0.3 | 0.2 |
Corporate and Other | Total regulated revenues | Revenues from contracts with customers | | | | |
Disaggregation of Operating Revenues | | | | |
Revenues from contracts with customers | 0 | 0 | 0 | 0 |
Corporate and Other | Electric | Revenues from contracts with customers | | | | |
Disaggregation of Operating Revenues | | | | |
Revenues from contracts with customers | 0 | 0 | 0 | 0 |
Corporate and Other | Natural gas | Revenues from contracts with customers | | | | |
Disaggregation of Operating Revenues | | | | |
Revenues from contracts with customers | 0 | 0 | 0 | 0 |
Corporate and Other | Other non-utility revenues | Revenues from contracts with customers | | | | |
Disaggregation of Operating Revenues | | | | |
Revenues from contracts with customers | $ 0 | $ 0 | $ 0 | $ 0 |