Debt (Tables)

12 Months Ended

Dec. 31, 2015

Debt Disclosure [Abstract]

Debt Outstanding

	December 31,
	2015			2014
	(in millions)
Revolving Credit Facility due 2019	$	—		$	—
6.05% Senior Notes due 2016	176.8			176.8
6.80% Senior Notes due 2018	134.0			134.0
6.80% Senior Notes due 2020	136.0			136.0
6.875% Senior Notes due 2021	625.0			625.0
5.375% Senior Notes due 2022	500.0			500.0
5.25% Senior Notes due 2023	650.0			650.0
Less: unamortized discount	(3.0		)	(3.7		)
Total principal amount of debt (including current portion)	2,218.8			2,218.1
Less: current portion of long-term debt	(176.8		)	—
Total long-term debt outstanding	$	2,042.0		$	2,218.1