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Schedule II - Valuation and Qualifying Accounts (Details) - USD ($) $ in Millions | 12 Months Ended
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Dec. 31, 2025 | Dec. 31, 2024 | Dec. 31, 2023
Schedule II - Valuation and Qualifying Accounts [Roll Forward] |  |  |
Balance at Beginning of Period | $ 148.2 | $ 158.5 | $ 213.0
Charges to Cost and Expense | 16.1 | 28.1 | 49.5
Other Additions | 0.0 | 0.0 | 0.0
(Deductions) | (45.2) | (38.4) | (104.0)
Balance at End of Period | 119.1 | 148.2 | 158.5
Allowance for credit losses |  |  |
Schedule II - Valuation and Qualifying Accounts [Roll Forward] |  |  |
Balance at Beginning of Period | 19.1 | 15.1 | 8.4
Charges to Cost and Expense | 2.4 | 9.9 | 12.7
Other Additions | 0.0 | 0.0 | 0.0
(Deductions) | (3.6) | (5.9) | (6.0)
Balance at End of Period | 17.9 | 19.1 | 15.1
Allowance for unbilled receivables and project close-out liabilities |  |  |
Schedule II - Valuation and Qualifying Accounts [Roll Forward] |  |  |
Balance at Beginning of Period | 64.4 | 83.0 | 117.0
Charges to Cost and Expense | 8.5 | 8.6 | 34.0
Other Additions | 0.0 | 0.0 | 0.0
(Deductions) | (32.7) | (27.2) | (68.0)
Balance at End of Period | 40.2 | 64.4 | 83.0
Valuation allowance for deferred tax assets |  |  |
Schedule II - Valuation and Qualifying Accounts [Roll Forward] |  |  |
Balance at Beginning of Period | 64.7 | 60.4 | 87.6
Charges to Cost and Expense | 5.2 | 9.6 | 2.8
Other Additions | 0.0 | 0.0 | 0.0
(Deductions) | (8.9) | (5.3) | (30.0)
Balance at End of Period | $ 61.0 | $ 64.7 | $ 60.4

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- Definition Amount of valuation and qualifying accounts and reserves. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 235 -SubTopic 10 -Name Accounting Standards Codification -Section S50 -Paragraph 5 -Publisher FASB -URI https://asc.fasb.org/1943274/2147480738/235-10-S50-5 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 235 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 4 -Subparagraph (SX 210.12-09(Column B)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480678/235-10-S99-4 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 235 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 4 -Subparagraph (SX 210.12-09(Column E)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480678/235-10-S99-4 + Details
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