Debt (Tables)

12 Months Ended

Dec. 31, 2019

Debt Disclosure [Abstract]

Summary of Debt

At December 31, 2019 and 2018, our long-term debt and interest rates on that debt were as follows (dollars in millions):

	December 31, 2019					December 31, 2018
	Amount		Interest Rate			Amount		Interest rate
Revolving Credit Facility, due August 2021	$	—		—	%	$	—		—	%
2.45% Senior Notes, net of discount of $0.4 million    as of December 31, 2018, due December 2020		—		—	%		499.6		2.45	%
3.90% Senior Notes, net of discount of $0.1 million    as of December 31, 2018, due June 2022		—		—	%		399.9		3.90	%
4.50% Senior Notes, net of discount of $0.8 million    and $1.0 million as of December 31, 2019 and 2018,    respectively, due November 2023		699.2		4.50	%		699.0		4.50	%
3.65% Senior Notes, net of discount of $0.6 million    and $0.7 million as of December 31, 2019 and 2018,    respectively, due September 2024		399.4		3.65	%		399.3		3.65	%
3.40% Senior Notes, net of discount of $1.3 million    and $1.5 million as of December 31, 2019 and 2018,    respectively, due December 2027		498.7		3.40	%		498.5		3.40	%
3.00% Senior Notes, net of discount of $0.7 million    as of December 31, 2019, due December 2029		499.3		3.00	%		—		—	%
4.05% Senior Notes, net of discount of $3.5 million    as of December 31, 2019, due December 2049		396.5		4.05	%		—		—	%
Total		2,493.1		3.77	%		2,496.3		3.64	%
Less current portion		—		—	%		—		—	%
Less unamortized debt issuance costs		16.3					12.6
Total long-term debt	$	2,476.8		3.77	%	$	2,483.7		3.64	%