Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Statement of Comprehensive Income [Abstract]
Net earnings	$ 197.6	$ 143.1	$ 583.1	$ 426.2
Other comprehensive income, net of tax:
Foreign currency translation adjustments (net of tax of $0.0 in 2018 and 2017)	(0.8)	8.2	(11.6)	19.2
Comprehensive income	$ 196.8	$ 151.3	$ 571.5	$ 445.4