Debt (Tables)

12 Months Ended

Dec. 31, 2023

Debt Disclosure [Abstract]

Summary of Debt

At December 31, 2023 and 2022, our long-term debt and interest rates on that debt were as follows (dollars in millions):

	December 31, 2023		December 31, 2022
	Amount		Amount
Revolving Credit Facility	$	—	$	—
3.65% Senior Notes, net of discount of $0.1 million    and $0.2 million as of December 31, 2023 and 2022,    respectively, due September 2024		399.9		399.8
3.40% Senior Notes, net of discount of $0.7 million    and $0.9 million as of December 31, 2023 and 2022,    respectively, due December 2027		499.3		499.1
3.00% Senior Notes, net of discount of $0.4 million    and $0.5 million as of December 31, 2023 and 2022,    respectively, due December 2029		499.6		499.5
5.70% Senior Notes, net of discount of $0.3 million    as of December 31, 2023, due December 2033		399.7		—
4.05% Senior Notes, net of discount of $3.3 million    as of both December 31, 2023 and 2022,    due December 2049		396.7		396.7
3.05% Senior Notes, net of discount of $3.5 million    and $3.6 million as of December 31, 2023 and 2022,    respectively, due October 2051		696.5		696.4
Total		2,891.7		2,491.5
Less current portion (a)		399.6		—
Less unamortized debt issuance costs		19.9		17.9
Total long-term debt	$	2,472.2	$	2,473.6

(a)The current portion of long-term debt excludes unamortized debt issuance costs of $0.3 million as of December 31, 2023.