Debt (Tables)

9 Months Ended

Sep. 30, 2024

Debt Disclosure [Abstract]

Summary of Debt

At September 30, 2024 and December 31, 2023, our long-term debt and interest rates on that debt were as follows (dollars in millions):

	September 30,		December 31,
	2024		2023
Revolving Credit Facility	$	—	$	—
3.65% Senior Notes, net of discount of $0.1 million    as of December 31, 2023, due September 2024		—		399.9
3.40% Senior Notes, net of discount of $0.6 million    and $0.7 million as of September 30, 2024 and December 31,    2023, respectively, due December 2027		499.4		499.3
3.00% Senior Notes, net of discount of $0.4 million    as of both September 30, 2024 and December    31, 2023, due December 2029		499.6		499.6
5.70% Senior Notes, net of discount of $0.3 million    as of both September 30, 2024 and December 31,    2023, due December 2033		399.7		399.7
4.05% Senior Notes, net of discount of $3.2 million    and $3.3 million as of September 30, 2024 and December 31,    2023, respectively, due December 2049		396.8		396.7
3.05% Senior Notes, net of discount of $3.4 million    and $3.5 million as of September 30, 2024 and December 31,    2023, respectively, due October 2051		696.6		696.5
Total		2,492.1		2,891.7
Less current portion (a)		—		399.6
Less unamortized debt issuance costs		18.4		19.9
Total long-term debt	$	2,473.7	$	2,472.2

(a)As of September 30, 2024, there are no unamortized debt issuance costs associated with the current portion of long-term debt, as the 2024 senior notes due September 2024 were repaid on September 15, 2024. As of December 31, 2023, the current portion of long-term debt excludes unamortized debt issuance costs of $0.3 million.