Consolidated Statements of Income - USD ($) shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Income Statement [Abstract]
REVENUE	$ 3,609.9	$ 3,567.2	$ 7,053.2	$ 6,977.5
Salary and service costs	2,617.8	2,566.0	5,160.7	5,057.8
Occupancy and other costs	297.7	293.0	589.3	593.2
Real estate and other repositioning costs	72.3	0.0	191.5	0.0
Charges arising from the effects of the war in Ukraine	0.0	0.0	0.0	113.4
Gain on disposition of subsidiary	(78.8)	0.0	(78.8)	0.0
Cost of services	2,909.0	2,859.0	5,862.7	5,764.4
Selling, general and administrative expenses	99.1	110.9	188.3	207.6
Depreciation and amortization	51.1	55.7	105.0	110.9
Total Operating Expenses	3,059.2	3,025.6	6,156.0	6,082.9
OPERATING INCOME	550.7	541.6	897.2	894.6
Interest Expense	57.5	51.2	112.4	102.2
Interest Income	30.1	11.1	65.7	19.3
INCOME BEFORE INCOME TAXES AND INCOME FROM EQUITY METHOD INVESTMENTS	523.3	501.5	850.5	811.7
Income Tax Expense	141.2	133.1	224.6	248.6
Income From Equity Method Investments	1.1	1.6	1.2	1.5
NET INCOME	383.2	370.0	627.1	564.6
Net Income Attributed To Noncontrolling Interests	16.9	21.6	33.3	42.4
NET INCOME - OMNICOM GROUP INC.	$ 366.3	$ 348.4	$ 593.8	$ 522.2
Net Income Per Share - Omnicom Group Inc.:
Basic	$ 1.84	$ 1.70	$ 2.96	$ 2.53
Diluted	$ 1.82	$ 1.68	$ 2.92	$ 2.51
Weighted Average Shares:
Basic	198.9	205.3	200.6	206.8
Diluted	201.6	206.9	203.1	208.3