Condensed Consolidated Statements of Income (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Revenue	$ 3,637.0	$ 3,561.0	$ 7,035.9	$ 6,868.2
Operating Expenses	3,114.0	3,054.6	6,141.1	5,999.3
Operating Income	523.0	506.4	894.8	868.9
Interest Expense	49.2	44.0	98.2	82.5
Interest Income	8.5	9.1	16.5	18.5
Income Before Income Taxes and Income From Equity Method Investments	482.3	471.5	813.1	804.9
Income Tax Expense	163.6	161.9	272.7	271.2
Income From Equity Method Investments	2.9	4.6	6.1	6.5
Net Income	321.6	314.2	546.5	540.2
Less: Net Income Attributed To Noncontrolling Interests	32.1	31.5	51.8	52.9
Net Income - Omnicom Group Inc.	$ 289.5	$ 282.7	$ 494.7	$ 487.3
Net Income Per Share - Omnicom Group Inc.:
Basic	$ 1.09	$ 1.03	$ 1.86	$ 1.76
Diluted	$ 1.09	$ 1.02	$ 1.85	$ 1.74
Dividends Declared Per Common Share	$ 0.40	$ 0.30	$ 0.80	$ 0.60