SEGMENT INFORMATION (Operating Revenue and Operating Income by Operating Segment) (Detail) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015 USD ($)	Sep. 30, 2014 USD ($)	Sep. 30, 2015 USD ($) segment	Sep. 30, 2014 USD ($)	Dec. 31, 2014 USD ($)
Segment Reporting Information [Line Items]
Operating revenue	$ 667.4	$ 613.4	$ 1,997.3	$ 1,811.8
Operating income	174.3	153.7	517.0	473.0
Total assets	4,541.4		$ 4,541.4		$ 4,674.2
Number of reportable segments | segment			4
U.S. Information Solutions
Segment Reporting Information [Line Items]
Operating revenue	312.3	278.6	$ 926.7	820.9
Operating income	123.4	104.3	382.8	312.4
Total assets	1,946.4		1,946.4		1,983.9
International
Segment Reporting Information [Line Items]
Operating revenue	148.8	148.1	436.0	438.9
Operating income	29.6	33.3	87.1	95.1
Total assets	875.7		875.7		983.7
Workforce Solutions
Segment Reporting Information [Line Items]
Operating revenue	139.0	122.5	434.0	361.6
Operating income	49.9	39.8	165.9	119.0
Total assets	1,270.3		1,270.3		1,271.3
Personal Solutions
Segment Reporting Information [Line Items]
Operating revenue	67.3	64.2	200.6	190.4
Operating income	18.1	20.8	54.8	58.3
Total assets	120.3		120.3		123.8
General Corporate
Segment Reporting Information [Line Items]
Operating income	(46.7)	$ (44.5)	(173.6)	$ (111.8)
Total assets	$ 328.7		$ 328.7		$ 311.5