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SEGMENT INFORMATION (Details) $ in Millions | 3 Months Ended | 6 Months Ended
--- | --- | ---
Jun. 30, 2024 USD ($) | Mar. 31, 2024 USD ($) | Jun. 30, 2023 USD ($) | Mar. 31, 2023 USD ($) | Jun. 30, 2024 USD ($) numberOfSegments | Jun. 30, 2023 USD ($)
Segment information |  |  |  |  |  |
Number of reportable segments | numberOfSegments |  |  |  |  | 6 |
Operating revenues | $ 1,772.0 |  | $ 1,830.0 |  | $ 4,452.2 | $ 4,718.1
Other operation and maintenance | 533.4 |  | 496.0 |  | 1,064.2 | 1,030.0
Depreciation and amortization | 336.6 |  | 313.9 |  | 670.0 | 619.4
Equity in earnings of transmission affiliates | 46.8 |  | 43.6 |  | 91.6 | 87.4
Interest expense | 200.6 |  | 178.7 |  | 392.6 | 350.9
Income tax expense (benefit) | 41.6 |  | 48.5 |  | 129.3 | 122.6
Net income (loss) | 210.0 |  | 290.0 |  | 832.6 | 797.6
Net income (loss) attributed to common shareholders | 211.3 | $ 622.3 | 289.7 | $ 507.5 | 833.6 | 797.2
External revenues |  |  |  |  |  |
Segment information |  |  |  |  |  |
Operating revenues | 1,772.0 |  | 1,830.0 |  | 4,452.2 | 4,718.1
Intersegment revenues |  |  |  |  |  |
Segment information |  |  |  |  |  |
Operating revenues | 0.0 |  | 0.0 |  | 0.0 | 0.0
Utility operations |  |  |  |  |  |
Segment information |  |  |  |  |  |
Other operation and maintenance | 516.4 |  | 478.9 |  | 1,033.9 | 998.1
Depreciation and amortization | 303.5 |  | 279.4 |  | 603.0 | 555.6
Equity in earnings of transmission affiliates | 0.0 |  | 0.0 |  | 0.0 | 0.0
Interest expense | 184.8 |  | 175.6 |  | 371.6 | 352.0
Income tax expense (benefit) | 44.9 |  | 65.8 |  | 204.9 | 184.9
Net income (loss) | 158.7 |  | 219.7 |  | 651.5 | 623.5
Net income (loss) attributed to common shareholders | 158.4 |  | 219.4 |  | 650.9 | 622.9
Utility operations | External revenues |  |  |  |  |  |
Segment information |  |  |  |  |  |
Operating revenues | 1,716.0 |  | 1,779.9 |  | 4,345.4 | 4,625.9
Utility operations | Intersegment revenues |  |  |  |  |  |
Segment information |  |  |  |  |  |
Operating revenues | 0.0 |  | 0.0 |  | 0.0 | 0.0
Reconciling eliminations |  |  |  |  |  |
Segment information |  |  |  |  |  |
Other operation and maintenance | (4.0) |  | (3.9) |  | (5.5) | (5.5)
Depreciation and amortization | (21.9) |  | (19.1) |  | (42.7) | (37.6)
Equity in earnings of transmission affiliates | 0.0 |  | 0.0 |  | 0.0 | 0.0
Interest expense | (89.7) |  | (88.8) |  | (180.0) | (173.3)
Income tax expense (benefit) | 0.0 |  | 0.0 |  | 0.0 | 0.0
Net income (loss) | 0.0 |  | 0.0 |  | 0.0 | 0.0
Net income (loss) attributed to common shareholders | 0.0 |  | 0.0 |  | 0.0 | 0.0
Reconciling eliminations | External revenues |  |  |  |  |  |
Segment information |  |  |  |  |  |
Operating revenues | 0.0 |  | 0.0 |  | 0.0 | 0.0
Reconciling eliminations | Intersegment revenues |  |  |  |  |  |
Segment information |  |  |  |  |  |
Operating revenues | $ (119.6) |  | (119.0) |  | $ (239.7) | (243.1)
ATC |  |  |  |  |  |
Segment information |  |  |  |  |  |
Ownership interest (as a percent) | 60.00% |  |  |  | 60.00% |
Equity in earnings of transmission affiliates | $ 46.2 |  | 43.1 |  | $ 90.6 | 86.0
ATC Holdco |  |  |  |  |  |
Segment information |  |  |  |  |  |
Ownership interest (as a percent) | 75.00% |  |  |  | 75.00% |
Equity in earnings of transmission affiliates | $ 0.6 |  | 0.5 |  | $ 1.0 | 1.4
Wisconsin | Operating Segments |  |  |  |  |  |
Segment information |  |  |  |  |  |
Operating revenues | 1,368.2 |  | 1,424.5 |  | 3,147.0 | 3,420.8
Wisconsin | Operating Segments | Utility operations |  |  |  |  |  |
Segment information |  |  |  |  |  |
Other operation and maintenance | 389.2 |  | 351.8 |  | 779.1 | 732.6
Depreciation and amortization | 228.3 |  | 210.3 |  | 452.9 | 417.6
Equity in earnings of transmission affiliates | 0.0 |  | 0.0 |  | 0.0 | 0.0
Interest expense | 157.3 |  | 150.1 |  | 315.1 | 300.7
Income tax expense (benefit) | 34.4 |  | 53.6 |  | 109.3 | 119.5
Net income (loss) | 132.4 |  | 185.9 |  | 399.1 | 443.4
Net income (loss) attributed to common shareholders | 132.1 |  | 185.6 |  | 398.5 | 442.8
Wisconsin | Operating Segments | Utility operations | External revenues |  |  |  |  |  |
Segment information |  |  |  |  |  |
Operating revenues | 1,368.2 |  | 1,424.5 |  | 3,147.0 | 3,420.8
Wisconsin | Operating Segments | Utility operations | Intersegment revenues |  |  |  |  |  |
Segment information |  |  |  |  |  |
Operating revenues | 0.0 |  | 0.0 |  | 0.0 | 0.0
Illinois | Operating Segments |  |  |  |  |  |
Segment information |  |  |  |  |  |
Operating revenues | 276.8 |  | 273.5 |  | 942.8 | 873.2
Illinois | Operating Segments | Utility operations |  |  |  |  |  |
Segment information |  |  |  |  |  |
Other operation and maintenance | 102.6 |  | 105.3 |  | 209.6 | 219.0
Depreciation and amortization | 63.7 |  | 58.5 |  | 127.2 | 117.0
Equity in earnings of transmission affiliates | 0.0 |  | 0.0 |  | 0.0 | 0.0
Interest expense | 23.5 |  | 21.4 |  | 48.5 | 43.0
Income tax expense (benefit) | 10.2 |  | 10.9 |  | 82.3 | 52.9
Net income (loss) | 25.7 |  | 30.1 |  | 213.2 | 143.2
Net income (loss) attributed to common shareholders | 25.7 |  | 30.1 |  | 213.2 | 143.2
Illinois | Operating Segments | Utility operations | External revenues |  |  |  |  |  |
Segment information |  |  |  |  |  |
Operating revenues | 276.8 |  | 273.5 |  | 942.8 | 873.2
Illinois | Operating Segments | Utility operations | Intersegment revenues |  |  |  |  |  |
Segment information |  |  |  |  |  |
Operating revenues | 0.0 |  | 0.0 |  | 0.0 | 0.0
Other States | Operating Segments |  |  |  |  |  |
Segment information |  |  |  |  |  |
Operating revenues | 71.0 |  | 81.9 |  | 255.6 | 331.9
Other States | Operating Segments | Utility operations |  |  |  |  |  |
Segment information |  |  |  |  |  |
Other operation and maintenance | 24.6 |  | 21.8 |  | 45.2 | 46.5
Depreciation and amortization | 11.5 |  | 10.6 |  | 22.9 | 21.0
Equity in earnings of transmission affiliates | 0.0 |  | 0.0 |  | 0.0 | 0.0
Interest expense | 4.0 |  | 4.1 |  | 8.0 | 8.3
Income tax expense (benefit) | 0.3 |  | 1.3 |  | 13.3 | 12.5
Net income (loss) | 0.6 |  | 3.7 |  | 39.2 | 36.9
Net income (loss) attributed to common shareholders | 0.6 |  | 3.7 |  | 39.2 | 36.9
Other States | Operating Segments | Utility operations | External revenues |  |  |  |  |  |
Segment information |  |  |  |  |  |
Operating revenues | 71.0 |  | 81.9 |  | 255.6 | 331.9
Other States | Operating Segments | Utility operations | Intersegment revenues |  |  |  |  |  |
Segment information |  |  |  |  |  |
Operating revenues | 0.0 |  | 0.0 |  | 0.0 | 0.0
Electric Transmission | Operating Segments |  |  |  |  |  |
Segment information |  |  |  |  |  |
Other operation and maintenance | 0.0 |  | 0.0 |  | 0.0 | 0.0
Depreciation and amortization | 0.0 |  | 0.0 |  | 0.0 | 0.0
Equity in earnings of transmission affiliates | 46.8 |  | 43.6 |  | 91.6 | 87.4
Interest expense | 4.9 |  | 4.8 |  | 9.7 | 9.6
Income tax expense (benefit) | 10.5 |  | 9.7 |  | 20.4 | 19.4
Net income (loss) | 31.4 |  | 29.1 |  | 61.5 | 58.4
Net income (loss) attributed to common shareholders | 31.4 |  | 29.1 |  | 61.5 | 58.4
Electric Transmission | Operating Segments | External revenues |  |  |  |  |  |
Segment information |  |  |  |  |  |
Operating revenues | 0.0 |  | 0.0 |  | 0.0 | 0.0
Electric Transmission | Operating Segments | Intersegment revenues |  |  |  |  |  |
Segment information |  |  |  |  |  |
Operating revenues | $ 0.0 |  | 0.0 |  | $ 0.0 | 0.0
Electric Transmission | ATC |  |  |  |  |  |
Segment information |  |  |  |  |  |
Ownership interest (as a percent) | 60.00% |  |  |  | 60.00% |
Electric Transmission | ATC Holdco |  |  |  |  |  |
Segment information |  |  |  |  |  |
Ownership interest (as a percent) | 75.00% |  |  |  | 75.00% |
Non-Utility Energy Infrastructure |  |  |  |  |  |
Segment information |  |  |  |  |  |
Natural gas storage needs provided to Wisconsin utilities |  |  |  |  | 33.00% |
Non-Utility Energy Infrastructure | Operating Segments |  |  |  |  |  |
Segment information |  |  |  |  |  |
Operating revenues | $ 175.6 |  | 169.0 |  | $ 346.5 | 335.2
Other operation and maintenance | 25.0 |  | 20.3 |  | 43.2 | 38.1
Depreciation and amortization | 49.6 |  | 48.4 |  | 98.7 | 91.1
Equity in earnings of transmission affiliates | 0.0 |  | 0.0 |  | 0.0 | 0.0
Interest expense | 24.1 |  | 25.1 |  | 48.2 | 45.0
Income tax expense (benefit) | (20.2) |  | (19.7) |  | (43.6) | (37.5)
Net income (loss) | 91.7 |  | 85.9 |  | 186.0 | 174.2
Net income (loss) attributed to common shareholders | 93.3 |  | 85.9 |  | 187.6 | 174.4
Non-Utility Energy Infrastructure | Operating Segments | External revenues |  |  |  |  |  |
Segment information |  |  |  |  |  |
Operating revenues | 56.0 |  | 50.0 |  | 106.8 | 92.1
Non-Utility Energy Infrastructure | Operating Segments | Intersegment revenues |  |  |  |  |  |
Segment information |  |  |  |  |  |
Operating revenues | 119.6 |  | 119.0 |  | 239.7 | 243.1
Corporate and Other | Operating Segments |  |  |  |  |  |
Segment information |  |  |  |  |  |
Operating revenues | 0.0 |  | 0.1 |  | 0.0 | 0.1
Other operation and maintenance | (4.0) |  | 0.7 |  | (7.4) | (0.7)
Depreciation and amortization | 5.4 |  | 5.2 |  | 11.0 | 10.3
Equity in earnings of transmission affiliates | 0.0 |  | 0.0 |  | 0.0 | 0.0
Interest expense | 76.5 |  | 62.0 |  | 143.1 | 117.6
Income tax expense (benefit) | 6.4 |  | (7.3) |  | (52.4) | (44.2)
Net income (loss) | (71.8) |  | (44.7) |  | (66.4) | (58.5)
Net income (loss) attributed to common shareholders | (71.8) |  | (44.7) |  | (66.4) | (58.5)
Corporate and Other | Operating Segments | External revenues |  |  |  |  |  |
Segment information |  |  |  |  |  |
Operating revenues | 0.0 |  | 0.1 |  | 0.0 | 0.1
Corporate and Other | Operating Segments | Intersegment revenues |  |  |  |  |  |
Segment information |  |  |  |  |  |
Operating revenues | $ 0.0 |  | $ 0.0 |  | $ 0.0 | $ 0.0

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