Debt (Tables)

12 Months Ended

Dec. 31, 2016

Debt Disclosure [Abstract]

Schedule of Debt

Debt consists of the following:

			December 31
			2016			2015
	Interest Rates	Maturities	(in millions of dollars)
Long-term Debt
Outstanding Principal
Senior Secured Notes issued 2007	Variable	2037	$	260.0		$	324.0
Senior Secured Notes acquired 2016	Variable	2038	3.5			—
Senior Notes issued 1998	7.000%	2018	200.0			200.0
Senior Notes issued 1998	6.750 - 7.250%	2028	365.8			365.8
Senior Notes issued 2002	7.375%	2032	39.5			39.5
Senior Notes issued 2010	5.625%	2020	400.0			400.0
Senior Notes issued 2012 and 2016	5.750%	2042	500.0			250.0
Senior Notes issued 2014	4.000%	2024	350.0			350.0
Senior Notes issued 2015	3.875%	2025	275.0			275.0
Senior Notes issued 2016	3.000%	2021	350.0			—
Medium-term Notes issued 1990 - 1996	7.000 - 7.190%	2023 - 2028	50.8			50.8
Junior Subordinated Debt Securities issued 1998	7.405%	2038	226.5			226.5
Fair Value Hedges Adjustment			(3.1		)	(2.7		)
Less:
Unamortized Net Premium (Discount)			9.8			(3.8		)
Unamortized Debt Issuance Costs			(28.4		)	(25.7		)
Total Long-term Debt			2,999.4			2,449.4
Short-term Debt
Outstanding Principal
Senior Notes issued 2009	7.125%	2016	—			350.0
Fair Value Hedges Adjustment			—			2.4
Less Unamortized Debt Issuance Costs			—			(0.4		)
Total Short-term Debt			—			352.0
Total Debt			$	2,999.4		$	2,801.4