Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Net Income	$ 262.4	$ 236.3
Cash flow hedge:
Loss for the period	0.0	(48.9)
Amortization of loss included in interest expense	1.4	0.0
Income tax effect	(0.6)	20.4
Other comprehensive income	0.8	(28.5)
Defined benefit pension plans and postemployment arrangements:
Amortization of prior service cost included in periodic benefit expense	2.0	1.8
Amortization of actuarial losses included in periodic benefit expense	1.9	1.5
Income tax effect	(1.8)	(1.0)
Other comprehensive income	2.1	2.3
Available-for-sale securities:
Unrealized gain for the period	0.2	0.0
Income tax effect	(0.1)	0.0
Other comprehensive income	0.1	0.0
Foreign currency translation adjustment	114.7	113.1
Other Comprehensive Income	117.7	86.9
Comprehensive Income	380.1	323.2
Comprehensive Income Attributed To Noncontrolling Interests	35.4	38.7
Comprehensive Income - Omnicom Group Inc.	$ 344.7	$ 284.5