CONDENSED CONSOLIDATED STATEMENTS OF INCOME - USD ($) shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
CONDENSED CONSOLIDATED STATEMENTS OF INCOME
Revenues	$ 1,190.0	$ 1,337.0
Type of Revenue	us-gaap:ServiceMember	us-gaap:ServiceMember
Expenses:
Cost of services	$ 683.4	$ 785.0
Type of Cost of Service	us-gaap:ServiceMember	us-gaap:ServiceMember
Selling, general, and administrative	$ 273.4	$ 300.8
Total expenses	956.8	1,085.8
Operating income	233.2	251.2
Other income/(expense):
Interest income	1.6	2.1
Interest expense	(32.9)	(39.7)
Other income, net		2.5
Total other expense, net	(31.3)	(35.1)
Income before income taxes	201.9	216.1
Provision for income taxes	25.2	43.0
Net income	$ 176.7	$ 173.1
Earnings per share:
Basic (USD per share)	$ 0.43	$ 0.40
Diluted (USD per share)	$ 0.42	$ 0.39
Weighted-average shares outstanding:
Basic (shares)	414.3	437.7
Diluted (shares)	418.3	439.9