Segment Information Operations (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Segments:
Revenue	$ 1,742.0	$ 1,676.0
OPERATING INCOME	20.9	7.8
Interest expense	22.6	20.9
Interest income	5.8	7.2
Other (expense) income, net	(17.1)	0.3
Loss before income taxes	(13.0)	(5.6)
Depreciation and amortization of fixed assets and intangible assets	38.0	38.7
Capital expenditures	27.0	20.2
IAN
Segments:
Revenue	1,401.6	1,345.1
OPERATING INCOME	39.7	31.4
Depreciation and amortization of fixed assets and intangible assets	27.6	29.4
Capital expenditures	20.3	12.1
CMG
Segments:
Revenue	340.4	330.9
OPERATING INCOME	20.4	19.9
Depreciation and amortization of fixed assets and intangible assets	4.8	4.6
Capital expenditures	1.5	1.1
Corporate and Other
Segments:
OPERATING INCOME	(39.2)	(43.5)
Depreciation and amortization of fixed assets and intangible assets	5.6	4.7
Capital expenditures	$ 5.2	$ 7.0