Consolidated Statements of Stockholders' Deficit - USD ($) $ in Millions	Total	Common Stock Issued	Additional Paid-In Capital	Retained Earnings	Accumulated Other Comprehensive Loss	Treasury Stock at Cost
Beginning balance at Dec. 31, 2022	$ (203.1)	$ 0.9	$ 1,155.2	$ 3,070.6	$ (90.6)	$ (4,339.2)
Beginning balance (in shares) at Dec. 31, 2022						51,700,000
Net income	315.2			315.2
Dividends	(76.8)			(76.8)
Foreign currency translation adjustments	14.3				14.3
Stock-based compensation expense	13.8		13.8
Change in cash flow hedges, net of tax	0.5				0.5
Treasury shares reissued for common stock	1.9		0.3			$ 1.6
Treasury stock purchases	(3.2)					(3.2)
Ending balance at Jun. 30, 2023	62.6	0.9	1,169.3	3,309.0	(75.8)	$ (4,340.8)
Ending balance (in shares) at Jun. 30, 2023						51,700,000
Beginning balance at Mar. 31, 2023	(125.9)	0.9	1,161.1	3,130.9	(78.6)	$ (4,340.2)
Beginning balance (in shares) at Mar. 31, 2023						51,700,000
Net income	217.2			217.2
Dividends	(39.1)			(39.1)
Foreign currency translation adjustments	7.5				7.5
Pension and post-retirement liability changes, net of tax	(0.3)				(0.3)
Stock-based compensation expense	7.7		7.7
Change in cash flow hedges, net of tax	(4.4)				(4.4)
Treasury shares reissued for common stock	1.1		0.5			$ 0.6
Treasury stock purchases	(1.2)					(1.2)
Ending balance at Jun. 30, 2023	62.6	0.9	1,169.3	3,309.0	(75.8)	$ (4,340.8)
Ending balance (in shares) at Jun. 30, 2023						51,700,000
Beginning balance at Dec. 31, 2023	$ 285.3	0.9	1,184.6	3,506.2	(56.9)	$ (4,349.5)
Beginning balance (in shares) at Dec. 31, 2023	51,588,103					51,600,000
Net income	$ 370.2			370.2
Dividends	(80.4)			(80.4)
Foreign currency translation adjustments	(9.5)				(9.5)
Pension and post-retirement liability changes, net of tax	(0.6)				(0.6)
Stock-based compensation expense	13.3		13.3
Change in cash flow hedges, net of tax	6.2				6.2
Treasury shares reissued for common stock	2.0					$ 2.0
Treasury shares reissued for common stock (in shares)						(100,000)
Treasury stock purchases	(9.1)					$ (9.1)
Ending balance at Jun. 30, 2024	$ 577.4	0.9	1,197.9	3,796.0	(60.8)	$ (4,356.6)
Ending balance (in shares) at Jun. 30, 2024	51,538,343					51,500,000
Beginning balance at Mar. 31, 2024	$ 368.8	0.9	1,190.6	3,591.1	(57.9)	$ (4,355.9)
Beginning balance (in shares) at Mar. 31, 2024						51,500,000
Net income	245.9			245.9
Dividends	(41.0)			(41.0)
Foreign currency translation adjustments	(6.2)				(6.2)
Pension and post-retirement liability changes, net of tax	(0.7)				(0.7)
Stock-based compensation expense	6.4		6.4
Change in cash flow hedges, net of tax	4.0				4.0
Treasury shares reissued for common stock	1.3		0.9			$ 0.4
Treasury stock purchases	(1.1)					(1.1)
Ending balance at Jun. 30, 2024	$ 577.4	$ 0.9	$ 1,197.9	$ 3,796.0	$ (60.8)	$ (4,356.6)
Ending balance (in shares) at Jun. 30, 2024	51,538,343					51,500,000