Debt (Tables)

12 Months Ended

Dec. 31, 2020

Debt Disclosure [Abstract]

Schedule of Debt

Debt consists of the following:

			December 31
			2020		2019
	Interest Rates	Maturities	(in millions of dollars)
Long-term Debt
Outstanding Principal
Senior Secured Notes issued 2007	Variable	2037	$	—	$	80.0
Senior Notes issued 1998	6.750 - 7.250%	2028	335.8		335.8
Senior Notes issued 2002	7.375%	2032	39.5		39.5
Senior Notes issued 2012 and 2016	5.750%	2042	500.0		500.0
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 2019	4.000%	2029	400.0		400.0
Senior Notes issued 2019	4.500%	2049	450.0		450.0
Senior Notes issued 2020	4.500%	2025	500.0		—
Medium-term Notes issued 1990 - 1996	7.000 - 7.190%	2023 - 2028	20.5		20.5
Junior Subordinated Debt Securities issued 1998	7.405%	2038	203.7		203.7
Junior Subordinated Debt Securities issued 2018	6.250%	2058	300.0		300.0
Fair Value Hedge Adjustment			—		(0.6)
Less:
Unamortized Net Premium			6.0		8.4
Unamortized Debt Issuance Costs			(34.8)		(35.4)
Total Long-term Debt			3,345.7		2,926.9
Short-term Debt
Outstanding Principal
Senior Notes issued 2010	5.625%	2020	—		400.0
Less Unamortized Debt Issuance Costs			—		(0.3)
Total Short-term Debt			—		399.7
Total Debt			$	3,345.7	$	3,326.6