Schedule II - Valuation and Qualifying Accounts (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Schedule II - Valuation and Qualifying Accounts [Roll Forward]
Balance at Beginning of Period	$ 213.0	$ 158.8	$ 116.7
Charges to Cost and Expense	49.5	23.6	79.2
Other Additions	0.0	69.9	0.0
(Deductions)	(104.0)	(39.3)	(37.1)
Balance at End of Period	158.5	213.0	158.8
Allowance for credit losses
Schedule II - Valuation and Qualifying Accounts [Roll Forward]
Balance at Beginning of Period	8.4	7.8	20.5
Charges to Cost and Expense	12.7	2.6	2.8
Other Additions	0.0	0.0	0.0
(Deductions)	(6.0)	(2.0)	(15.5)
Balance at End of Period	15.1	8.4	7.8
Allowance for unbilled receivables and project close-out liabilities
Schedule II - Valuation and Qualifying Accounts [Roll Forward]
Balance at Beginning of Period	117.0	96.8	50.4
Charges to Cost and Expense	34.0	9.4	67.0
Other Additions	0.0	40.3	0.0
(Deductions)	(68.0)	(29.5)	(20.6)
Balance at End of Period	83.0	117.0	96.8
Valuation allowance for deferred tax assets
Schedule II - Valuation and Qualifying Accounts [Roll Forward]
Balance at Beginning of Period	87.6	54.2	45.8
Charges to Cost and Expense	2.8	11.6	9.4
Other Additions	0.0	29.6	0.0
(Deductions)	(30.0)	(7.8)	(1.0)
Balance at End of Period	$ 60.4	$ 87.6	$ 54.2