Contract Liabilities and Other Disclosures (Tables)

12 Months Ended

Dec. 31, 2020

Contract Liabilities And Other Disclosures [Abstract]

Schedule of contract related balances (other than deferred income disclosed above)

	Accounts Receivable		Unbilled Accounts Receivable		Deferred Income			Customer Prepayments and Deposits
	(in millions)
At December 31, 2020	$	30.4	$	8.2	$	(22.9	)	$	(1.6	)
At December 31, 2019	$	24.5	$	15.3	$	(27.8	)	$	(1.9	)
At December 31, 2018	$	11.5	$	11.0	$	(32.0	)	$	(3.6	)