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Goodwill (Details) - USD ($) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2016 | Dec. 31, 2015
Goodwill |  |
Accumulated impairment losses | $ 0.0 |
Goodwill impairment loss | 0.0 |
Changes to goodwill balances by segment |  |
Goodwill balance as of January 1 | 3,023.5 | $ 441.9
Adjustment to Integrys purchase price allocation | 22.7 | 0.0
Acquisition of Integrys | 0.0 | 2,581.6
Goodwill balance as of December 31 | 3,046.2 | 3,023.5
Wisconsin |  |
Changes to goodwill balances by segment |  |
Goodwill balance as of January 1 | 2,109.5 | 441.9
Adjustment to Integrys purchase price allocation | (5.2) | 0.0
Acquisition of Integrys | 0.0 | 1,667.6
Goodwill balance as of December 31 | 2,104.3 | 2,109.5
Illinois |  |
Changes to goodwill balances by segment |  |
Goodwill balance as of January 1 | 731.2 | 0.0
Adjustment to Integrys purchase price allocation | 27.5 | 0.0
Acquisition of Integrys | 0.0 | 731.2
Goodwill balance as of December 31 | 758.7 | 731.2
Other States |  |
Changes to goodwill balances by segment |  |
Goodwill balance as of January 1 | 182.8 | 0.0
Adjustment to Integrys purchase price allocation | 0.4 | 0.0
Acquisition of Integrys | 0.0 | 182.8
Goodwill balance as of December 31 | $ 183.2 | $ 182.8

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