Acquisitions - Assets Acquired and Liabilities Assumed (Details) - USD ($) $ in Millions	Sep. 01, 2021	Sep. 30, 2021	Dec. 31, 2020
Recognized amounts of identifiable assets acquired and liabilities assumed:
Goodwill		$ 2,539.5	$ 1,641.7
ASP Henry Holdings, Inc.
Acquisitions
Consideration paid	$ 1,608.2
Recognized amounts of identifiable assets acquired and liabilities assumed:
Cash and cash equivalents	34.3
Receivables, net	79.0
Inventories	59.4
Prepaid expenses and other current assets	10.5
Property, plant and equipment	53.6
Definite-lived intangible assets	735.1
Other long-term assets	3.6
Accounts payable	(77.9)
Accrued and other current liabilities	(28.7)
Short-term debt	(1.0)
Contract liabilities	(2.6)
Other long-term debt	(0.8)
Other long-term liabilities	(5.9)
Deferred tax liabilities	(153.4)
Total identifiable net assets	705.2
Goodwill	$ 903.0