Condensed Consolidated Statements of Changes in Stockholders' Equity (unaudited) - USD ($) $ in Millions	Total	Cumulative Effect, Period Of Adoption, Adjustment	Common stock	Additional paid-in capital	Retained earnings	Retained earnings Cumulative Effect, Period Of Adoption, Adjustment	Accumulated other comprehensive loss	Treasury stock
Balance at Dec. 31, 2018	$ 7,738.5		$ 1.1	$ 1,751.5	$ 6,247.7		$ (243.3)	$ (18.5)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings	369.6				369.6
Stock option exercises	36.8			36.8
Treasury stock sold	2.2			2.1				0.1
Currency translation adjustments	28.7						28.7
Stock-based compensation	24.3			24.3
Restricted stock activity	(14.8)			(14.8)
Dividends declared	(47.9)				(47.9)
Balance at Mar. 31, 2019	8,137.4		1.1	1,799.9	6,569.4		(214.6)	(18.4)
Balance at Dec. 31, 2019	9,491.9		1.1	1,903.9	7,818.0		(212.8)	(18.3)
Balance (ASC 326) at Dec. 31, 2019		$ (1.7)				$ (1.7)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings	240.3				240.3
Stock option exercises	22.9			22.9
Treasury stock sold	2.8			2.7				0.1
Currency translation adjustments	(128.2)						(128.2)
Stock-based compensation	27.6			27.6
Restricted stock activity	(10.8)			(10.8)
Dividends declared	(53.5)				(53.5)
Balance at Mar. 31, 2020	$ 9,591.3		$ 1.1	$ 1,946.3	$ 8,003.1		$ (341.0)	$ (18.2)