Investments in Affiliates and Other Related Party Transactions - Summarized Income Statement Data for Affiliates Accounted for under Equity Method (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income statement data:
Net sales	$ 1,520.2	$ 2,000.4	$ 2,186.4
Gross profit	75.9	172.8	200.6
Income before provision for income taxes	60.0	169.6	195.3
Net income attributable to affiliates	$ 42.2	$ 117.8	$ 155.4