Condensed Consolidated Statements of Comprehensive Income (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Net Income	$ 321.6	$ 314.2	$ 546.5	$ 540.2
Unrealized gain on available-for-sale securities, net of income taxes of $0.1 for the three months and $0.2 for the six months ended June 30, 2013	0.1	0	0.3	0
Foreign currency translation adjustment, net of income taxes of ($63.5) and ($66.2) for the three months and ($158.0) and ($16.4) for the six months ended June 30, 2013 and 2012, respectively	(123.3)	(128.5)	(306.6)	(31.8)
Defined benefit pension and postemployment plans adjustment, net of income taxes of $1.1 and $0.9 for the three months and $2.4 and $1.6 for the six months ended June 30, 2013 and 2012, respectively	1.7	1.3	3.4	2.4
Other Comprehensive Income	(121.5)	(127.2)	(302.9)	(29.4)
Comprehensive Income	200.1	187.0	243.6	510.8
Less: Comprehensive Income attributed to noncontrolling interests	7.6	24.4	16.8	48.0
Comprehensive Income - Omnicom Group Inc.	$ 192.5	$ 162.6	$ 226.8	$ 462.8