Consolidated Statements of Income - USD ($) shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Income Statement [Abstract]
REVENUE	$ 3,882.6	$ 3,578.1	$ 11,366.9	$ 10,631.3
Salary and service costs	2,796.0	2,586.5	8,288.7	7,747.2
Occupancy and other costs	325.6	288.6	953.9	877.9
Real estate and other repositioning costs	0.0	0.0	57.8	191.5
Gain on disposition of subsidiary	0.0	0.0	0.0	(78.8)
Cost of services	3,121.6	2,875.1	9,300.4	8,737.8
Selling, general and administrative expenses	99.5	89.8	295.8	278.1
Depreciation and amortization	61.4	52.4	181.4	157.4
Total Operating Expenses	3,282.5	3,017.3	9,777.6	9,173.3
OPERATING INCOME	600.1	560.8	1,589.3	1,458.0
Interest Expense	66.4	53.5	182.9	165.9
Interest Income	26.0	15.2	74.0	80.9
INCOME BEFORE INCOME TAXES AND INCOME FROM EQUITY METHOD INVESTMENTS	559.7	522.5	1,480.4	1,373.0
Income Tax Expense	150.2	136.1	389.9	360.7
Income From Equity Method Investments	0.4	1.9	4.6	3.1
NET INCOME	409.9	388.3	1,095.1	1,015.4
Net Income Attributed To Noncontrolling Interests	24.0	16.4	62.5	49.7
NET INCOME - OMNICOM GROUP INC.	$ 385.9	$ 371.9	$ 1,032.6	$ 965.7
Net Income Per Share - Omnicom Group Inc.:
Basic	$ 1.97	$ 1.88	$ 5.25	$ 4.84
Diluted	$ 1.95	$ 1.86	$ 5.19	$ 4.78
Weighted Average Shares:
Basic	195.6	198.1	196.5	199.7
Diluted	198.2	199.9	198.9	202.0