Consolidated Statements of Stockholders' Equity - USD ($) shares in Thousands, $ in Millions	Total	Common Stock	Additional paid-in capital	Retained earnings	Accumulated other comprehensive earnings	Treasury stock
Beginning balance (in shares) at Dec. 31, 2015		100,900
Beginning balance at Dec. 31, 2015	$ 5,298.9	$ 1.0	$ 1,419.3	$ 4,110.5	$ (212.8)	$ (19.1)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings	658.6	$ 0.0	0.0	658.6	0.0	0.0
Stock option exercises (in shares)		400
Stock option exercises	28.0	$ 0.0	28.0	0.0	0.0	0.0
Treasury stock sold (in shares)		0
Treasury stock sold	3.3	$ 0.0	3.1	0.0	0.0	0.2
Currency translation adjustments, net of tax	(111.9)	0.0	0.0	0.0	(111.9)	0.0
Stock based compensation	77.9	$ 0.0	77.9	0.0	0.0	0.0
Restricted stock activity (in shares)		400
Restricted stock activity	(18.0)	$ 0.0	(18.0)	0.0	0.0	0.0
Stock option tax benefit, net of shortfalls	(8.1)	0.0	(8.1)	0.0	0.0	0.0
Conversion of senior subordinated convertible notes	(13.1)	0.0	(13.1)	0.0	0.0	0.0
Dividends declared	(126.7)	$ 0.0	0.0	(126.7)	0.0	0.0
Ending balance (in shares) at Dec. 31, 2016		101,700
Ending balance at Dec. 31, 2016	5,788.9	$ 1.0	1,489.1	4,642.4	(324.7)	(18.9)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings	$ 971.8	$ 0.0	0.0	971.8	0.0	0.0
Stock option exercises (in shares)	645	600
Stock option exercises	$ 61.3	$ 0.0	61.3	0.0	0.0	0.0
Treasury stock sold (in shares)		0
Treasury stock sold	4.2	$ 0.0	4.0	0.0	0.0	0.2
Currency translation adjustments, net of tax	138.5	0.0	0.0	0.0	138.5	0.0
Stock based compensation	81.3	$ 0.0	81.3	0.0	0.0	0.0
Restricted stock activity (in shares)		200
Restricted stock activity	(32.8)	$ 0.0	(32.8)	0.0	0.0	0.0
Dividends declared	$ (149.6)	$ 0.0	0.0	(149.6)	0.0	0.0
Ending balance (in shares) at Dec. 31, 2017	102,500	102,500
Ending balance at Dec. 31, 2017	$ 6,863.6	$ 1.0	1,602.9	5,464.6	(186.2)	(18.7)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings	$ 944.4	$ 0.0	0.0	944.4	0.0	0.0
Stock option exercises (in shares)	650	600
Stock option exercises	$ 58.8	$ 0.1	58.7	0.0	0.0	0.0
Treasury stock sold (in shares)		0
Treasury stock sold	5.4	$ 0.0	5.2	0.0	0.0	0.2
Currency translation adjustments, net of tax	(57.1)	0.0	0.0	0.0	(57.1)	0.0
Stock based compensation	132.9	$ 0.0	132.9	0.0	0.0	0.0
Restricted stock activity (in shares)		300
Restricted stock activity	(48.2)	$ 0.0	(48.2)	0.0	0.0	0.0
Dividends declared	$ (175.6)	$ 0.0	0.0	(175.6)	0.0	0.0
Ending balance (in shares) at Dec. 31, 2018	103,400	103,400
Ending balance at Dec. 31, 2018	$ 7,738.5	$ 1.1	$ 1,751.5	$ 6,247.7	$ (243.3)	$ (18.5)