Supplemental Guarantor Information - Condensed Consolidating Statements of Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Supplemental Guarantor Information [Line Items]
Comprehensive income (loss)	$ 180.6	$ 143.6	$ 471.4	$ 366.4
Consolidating Adjustments
Supplemental Guarantor Information [Line Items]
Comprehensive income (loss)	(410.6)	(330.0)	(1,089.5)	(886.4)
Parent Guarantor | Reportable Legal Entities
Supplemental Guarantor Information [Line Items]
Comprehensive income (loss)	180.6	143.6	471.4	366.4
Subsidiary Issuer | Reportable Legal Entities
Supplemental Guarantor Information [Line Items]
Comprehensive income (loss)	180.7	143.6	471.7	366.4
Guarantor Subsidiaries | Reportable Legal Entities
Supplemental Guarantor Information [Line Items]
Comprehensive income (loss)	215.0	162.4	587.8	453.6
Non-Guarantor Subsidiaries | Reportable Legal Entities
Supplemental Guarantor Information [Line Items]
Comprehensive income (loss)	14.9	24.0	30.0	66.4
Co-Issuer | Reportable Legal Entities
Supplemental Guarantor Information [Line Items]
Comprehensive income (loss)	$ 0.0	$ 0.0	$ 0.0	$ 0.0