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	619.3				619.3
Stock option exercises	49.1			49.1
Treasury stock sold	3.6			3.5				0.1
Currency translation adjustments	0.1						0.1
Stock-based compensation	52.5			52.5
Restricted stock activity	(16.1)			(16.1)
Dividends declared	(96.0)				(96.0)
Balance at Jun. 30, 2019	8,351.0		1.1	1,840.5	6,771.0		(243.2)	(18.4)
Balance at Mar. 31, 2019	8,137.4		1.1	1,799.9	6,569.4		(214.6)	(18.4)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings	249.7				249.7
Stock option exercises	12.3			12.3
Treasury stock sold	1.4			1.4
Currency translation adjustments	(28.6)						(28.6)
Stock-based compensation	28.2			28.2
Restricted stock activity	(1.3)			(1.3)
Dividends declared	(48.1)				(48.1)
Balance at Jun. 30, 2019	8,351.0		1.1	1,840.5	6,771.0		(243.2)	(18.4)
Balance at Dec. 31, 2019	9,491.9	$ (1.7)	1.1	1,903.9	7,818.0	$ (1.7)	(212.8)	(18.3)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings	459.5				459.5
Stock option exercises	63.0			63.0
Treasury stock sold	4.5			4.4				0.1
Currency translation adjustments	(72.0)						(72.0)
Stock-based compensation	56.9			56.9
Restricted stock activity	(15.3)			(15.3)
Dividends declared	(107.1)				(107.1)
Balance at Jun. 30, 2020	$ 9,879.7		1.1	2,012.9	8,168.7		(284.8)	(18.2)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Accounting Standards Update [Extensible List]	us-gaap:AccountingStandardsUpdate201613Member
Balance at Mar. 31, 2020	$ 9,591.3		1.1	1,946.3	8,003.1		(341.0)	(18.2)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings	219.2				219.2
Stock option exercises	40.1			40.1
Treasury stock sold	1.7			1.7				0.0
Currency translation adjustments	56.2						56.2
Stock-based compensation	29.3			29.3
Restricted stock activity	(4.5)			(4.5)
Dividends declared	(53.6)				(53.6)
Balance at Jun. 30, 2020	$ 9,879.7		$ 1.1	$ 2,012.9	$ 8,168.7		$ (284.8)	$ (18.2)