Changes in Stockholders' Equity (Changes in Accumulated Other Comprehensive Income) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance beginning of period	$ 3,443.8	$ 3,018.0
Other comprehensive income (loss), net of reclassification adjustments	136.7	(7.5)
Balance end of period	3,674.9	3,124.7
Defined Benefit Pension Plans
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance beginning of period	(230.4)
Other comprehensive income (loss) before reclassifications	0.0
Net losses (gains) reclassified from accumulated other comprehensive loss	1.7
Other comprehensive income (loss), net of reclassification adjustments	1.7
Balance end of period	(228.7)
Deferred Net (Losses) Gains on Derivatives
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance beginning of period	(0.4)
Other comprehensive income (loss) before reclassifications	(2.4)
Net losses (gains) reclassified from accumulated other comprehensive loss	(0.9)
Other comprehensive income (loss), net of reclassification adjustments	(3.3)
Balance end of period	(3.7)
Cumulative Translation Adjustment
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance beginning of period	(1,540.1)
Other comprehensive income (loss) before reclassifications	137.5
Net losses (gains) reclassified from accumulated other comprehensive loss	0.0
Other comprehensive income (loss), net of reclassification adjustments	137.5
Balance end of period	(1,402.6)
Accumulated Other Comprehensive Loss
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance beginning of period	(1,770.9)	(1,810.8)
Other comprehensive income (loss) before reclassifications	135.1
Net losses (gains) reclassified from accumulated other comprehensive loss	0.8
Other comprehensive income (loss), net of reclassification adjustments	135.9
Balance end of period	$ (1,635.0)	$ (1,817.9)