Revenue - Change in Contract Assets and Liabilities (Details) $ in Millions	3 Months Ended
	Mar. 31, 2022 USD ($)
Contract assets
Beginning accounts receivable, net of allowances	$ 236.3
Change in accounts receivable	16.7
Ending accounts receivable, net of allowances	253.0
Beginning unbilled contract revenue	93.5
Change in unbilled contract revenue	32.5
Ending unbilled contract revenue	$ 126.0
Change in accounts receivable (as a percentage)	7.10%
Change in unbilled contract revenue (as a percentage)	34.80%
Contract liabilities
Beginning balance customer advances and billings in excess of contract revenue	$ 148.5
Change in customer advances and billings in excess of contract revenue	29.4
Ending balance customer advances and billings in excess of contract revenue	177.9
Beginning long-term deferred revenue	0.4
Change in long-term deferred revenue	(0.3)
Ending long-term deferred revenue	$ 0.1
Change in customer advances and billings in excess of contract revenue (as a percentage)	19.80%
Change in long-term deferred revenue (as a percentage)	(75.00%)