Consolidated Statements of Income - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Income Statement [Abstract]
Revenue	$ 3,410.3	$ 3,426.9
Salary and service costs	2,491.8	2,545.0
Occupancy and other costs	300.2	291.6
Charges arising from the effects of the war in Ukraine	113.4	0.0
Cost of services	2,905.4	2,836.6
Selling, general and administrative expenses	96.7	71.6
Depreciation and amortization	55.2	53.3
Operating Expenses	3,057.3	2,961.5
Operating Profit	353.0	465.4
Interest Expense	51.0	53.8
Interest Income	8.2	6.3
Income Before Income Taxes and Loss From Equity Method Investments	310.2	417.9
Income Tax Expense	115.5	111.9
Loss From Equity Method Investments	(0.1)	0.0
Net Income	194.6	306.0
Net Income Attributed To Noncontrolling Interests	20.8	18.2
Net Income - Omnicom Group Inc.	$ 173.8	$ 287.8
Net Income Per Share - Omnicom Group Inc.:
Basic	$ 0.83	$ 1.33
Diluted	$ 0.83	$ 1.33