Consolidated Statements of Income - USD ($) shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Income Statement [Abstract]
REVENUE	$ 3,853.8	$ 3,609.9	$ 7,484.3	$ 7,053.2
Salary and service costs	2,800.1	2,617.8	5,492.7	5,160.7
Occupancy and other costs	314.2	297.7	628.3	589.3
Real estate and other repositioning costs	57.8	72.3	57.8	191.5
Gain (Loss) on Disposition of Business	0.0	(78.8)	0.0	(78.8)
Cost of services	3,172.1	2,909.0	6,178.8	5,862.7
Selling, general and administrative expenses	111.0	99.1	196.3	188.3
Depreciation and amortization	60.4	51.1	120.0	105.0
Total Operating Expenses	3,343.5	3,059.2	6,495.1	6,156.0
OPERATING INCOME	510.3	550.7	989.2	897.2
Interest Expense	62.7	57.5	116.5	112.4
Interest Income	21.0	30.1	48.0	65.7
INCOME BEFORE INCOME TAXES AND INCOME FROM EQUITY METHOD INVESTMENTS	468.6	523.3	920.7	850.5
Income Tax Expense	123.7	141.2	239.7	224.6
Income From Equity Method Investments	3.3	1.1	4.2	1.2
NET INCOME	348.2	383.2	685.2	627.1
Net Income Attributed To Noncontrolling Interests	20.1	16.9	38.5	33.3
NET INCOME - OMNICOM GROUP INC.	$ 328.1	$ 366.3	$ 646.7	$ 593.8
Net Income Per Share - Omnicom Group Inc.:
Basic	$ 1.67	$ 1.84	$ 3.28	$ 2.96
Diluted	$ 1.65	$ 1.82	$ 3.24	$ 2.92
Weighted Average Shares (millions):
Basic	195.9	198.9	196.9	200.6
Diluted	198.5	201.6	199.3	203.1