Consolidated Statements of Income - USD ($) shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Income Statement [Abstract]
REVENUE	$ 3,630.5	$ 3,443.3
Salary and service costs	2,692.6	2,542.9
Occupancy and other costs	314.1	291.6
Real estate repositioning costs	0.0	119.2
Cost of services	3,006.7	2,953.7
Selling, general and administrative expenses	85.3	89.2
Depreciation and amortization	59.6	53.9
Total Operating Expenses	3,151.6	3,096.8
OPERATING INCOME	478.9	346.5
Interest Expense	53.8	54.9
Interest Income	27.0	35.6
INCOME BEFORE INCOME TAXES AND INCOME FROM EQUITY METHOD INVESTMENTS	452.1	327.2
Income Tax Expense	116.0	83.4
Income From Equity Method Investments	0.9	0.1
NET INCOME	337.0	243.9
Net Income Attributed To Noncontrolling Interests	18.4	16.4
NET INCOME - OMNICOM GROUP INC.	$ 318.6	$ 227.5
Net Income Per Share - Omnicom Group Inc.:
Basic	$ 1.61	$ 1.13
Diluted	$ 1.59	$ 1.11
Weighted Average Shares (millions):
Basic	197.9	202.2
Diluted	200.1	204.5