Debt - Interest Income, Expense and Other Financing Costs (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Interest income, expense and other financing costs
Interest income	$ 3.9	$ 6.0	$ 4.5
Interest expense and other financing costs	(74.8)	(66.3)	(43.7)
Interest expense and other financing costs, net	$ (71.0)	$ (60.3)	$ (39.2)

Amount of the cost of borrowed funds accounted for as interest expense.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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Name:	us-gaap_InterestExpense
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration