Stockholders' Equity (Changes in Accumulated Other Comprehensive Income (Loss)) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Stockholders' equity, beginning of period	$ 3,882.6	$ 3,443.8	$ 3,018.0
Other comprehensive income (loss), net of reclassification adjustments	95.0	(31.3)	39.5
Stockholders' equity, end of period	4,656.8	3,882.6	3,443.8
Accumulated Other Comprehensive Loss
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Stockholders' equity, beginning of period	(1,803.1)	(1,770.9)	(1,810.8)
Other comprehensive (loss) income before reclassifications	77.7	(52.7)
Net losses reclassified from accumulated other comprehensive loss	17.3	20.5
Other comprehensive income (loss), net of reclassification adjustments	95.0	(32.2)	39.9
Stockholders' equity, end of period	(1,708.1)	(1,803.1)	(1,770.9)
Defined Benefit Pension Plans
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Stockholders' equity, beginning of period	(231.2)	(230.4)	(313.3)
Other comprehensive (loss) income before reclassifications	(15.7)	(7.2)
Net losses reclassified from accumulated other comprehensive loss	8.3	6.4
Other comprehensive income (loss), net of reclassification adjustments	(7.4)	(0.8)	82.9
Stockholders' equity, end of period	(238.6)	(231.2)	(230.4)
Cumulative Translation Adjustment
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Stockholders' equity, beginning of period	(1,571.0)	(1,540.1)	(1,495.0)
Other comprehensive (loss) income before reclassifications	102.3	(30.9)
Net losses reclassified from accumulated other comprehensive loss	0.0	0.0
Other comprehensive income (loss), net of reclassification adjustments	102.3	(30.9)	(45.1)
Stockholders' equity, end of period	(1,468.7)	(1,571.0)	(1,540.1)
Deferred gains and losses on derivatives
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Stockholders' equity, beginning of period	(0.9)	(0.4)	(2.5)
Other comprehensive (loss) income before reclassifications	(8.9)	(14.6)	5.1
Net losses reclassified from accumulated other comprehensive loss	9.0	14.1	(3.0)
Other comprehensive income (loss), net of reclassification adjustments	0.1	(0.5)	2.1
Stockholders' equity, end of period	$ (0.8)	$ (0.9)	$ (0.4)