Debt (Tables)

12 Months Ended

Dec. 31, 2021

Debt Disclosure [Abstract]

Summary of Debt

At December 31, 2021 and 2020, our long-term debt and interest rates on that debt were as follows (dollars in millions):

	December 31, 2021		December 31, 2020
	Amount		Amount
Revolving Credit Facility	$	—	$	—
4.50% Senior Notes, net of discount of $0.6 million   as of December 31, 2020, due November 2023		—		699.4
3.65% Senior Notes, net of discount of $0.4 million    and $0.5 million as of December 31, 2021 and 2020,    respectively, due September 2024		399.6		399.5
3.40% Senior Notes, net of discount of $1.0 million    and $1.2 million as of December 31, 2021 and 2020,    respectively, due December 2027		499.0		498.8
3.00% Senior Notes, net of discount of $0.5 million    and $0.6 million as of December 31, 2021 and 2020,    respectively, due December 2029		499.5		499.4
4.05% Senior Notes, net of discount of $3.4 million    as of both December 31, 2021 and 2020, due December 2049		396.6		396.6
3.05% Senior Notes, net of discount of $3.7 million    as of December 31, 2021, due October 2051		696.3		—
Total		2,491.0		2,493.7
Less unamortized debt issuance costs		19.5		14.3
Total long-term debt	$	2,471.5	$	2,479.4