Consolidated Statements of Operations (Unaudited) - USD ($) shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Income Statement [Abstract]
Revenues from services	$ 4,619.1	$ 5,044.9
Cost of services	3,895.1	4,240.1
Gross profit	724.0	804.8
Selling and administrative expenses	686.3	699.3
Operating profit	37.7	105.5
Interest and other expenses	20.5	11.9
Earnings before income taxes	17.2	93.6
Provision for income taxes	15.5	40.1
Net earnings	$ 1.7	$ 53.5
Net earnings per share - basic (in dollars per share)	$ 0.03	$ 0.88
Net earnings per share - diluted (in dollars per share)	$ 0.03	$ 0.88
Weighted average shares - basic (in shares)	58.7	60.6
Weighted average shares - diluted (in shares)	59.0	61.0