Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Statement of Comprehensive Income [Abstract]
Net earnings	$ 578.6	$ 499.4	$ 516.4
Other comprehensive income (loss), net of tax:
Foreign currency translation adjustments (net of tax of $0.0 in 2017, 2016, and 2015)	22.2	(0.9)	(38.6)
Comprehensive income	$ 600.8	$ 498.5	$ 477.8