CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
REVENUE:
Revenue before billable expenses	$ 2,135,600,000	$ 2,242,700,000	$ 6,304,600,000	$ 6,752,700,000
Billable expenses	358,400,000	386,100,000	1,048,800,000	1,082,000,000
Total revenue	2,494,000,000	2,628,800,000	7,353,400,000	7,834,700,000
OPERATING EXPENSES:
Salaries and related expenses	1,370,300,000	1,464,000,000	4,162,900,000	4,594,400,000
Office and other direct expenses	304,500,000	327,100,000	948,900,000	1,007,600,000
Billable expenses	358,400,000	386,100,000	1,048,800,000	1,082,000,000
Cost of services	2,033,200,000	2,177,200,000	6,160,600,000	6,684,000,000
Selling, general and administrative expenses	50,300,000	20,800,000	137,100,000	86,400,000
Depreciation and amortization	62,000,000.0	65,300,000	184,200,000	195,500,000
Goodwill, Impairment Loss	0.0	232,100,000	0	232,100,000
Restructuring charges	129,500,000	500,000	450,800,000	1,400,000
Total operating expenses	2,275,000,000	2,495,900,000	6,932,700,000	7,199,400,000
OPERATING INCOME	219,000,000.0	132,900,000	420,700,000	635,300,000
EXPENSES AND OTHER INCOME:
Interest expense	(48,900,000)	(54,900,000)	(149,500,000)	(175,600,000)
Interest income	24,300,000	34,200,000	85,100,000	119,500,000
Other expense, net	(5,700,000)	(2,700,000)	(44,000,000.0)	(13,400,000)
Total (expenses) and other income	(30,300,000)	(23,400,000)	(108,400,000)	(69,500,000)
INCOME BEFORE INCOME TAXES	188,700,000	109,500,000	312,300,000	565,800,000
Provision for income taxes	58,700,000	85,300,000	104,100,000	208,200,000
INCOME OF CONSOLIDATED COMPANIES	130,000,000.0	24,200,000	208,200,000	357,600,000
Equity in net loss of unconsolidated affiliates	(2,900,000)	0.0	(2,800,000)	(200,000)
NET INCOME	127,100,000	24,200,000	205,400,000	357,400,000
Net income attributable to non-controlling interests	(2,900,000)	(4,100,000)	(4,100,000)	(12,400,000)
NET INCOME AVAILABLE TO IPG COMMON STOCKHOLDERS	$ 124,200,000	$ 20,100,000	$ 201,300,000	$ 345,000,000.0
Earnings per share available to IPG common stockholders:
Basic (in dollars per share)	$ 0.34	$ 0.05	$ 0.55	$ 0.92
Diluted (in dollars per share)	$ 0.34	$ 0.05	$ 0.54	$ 0.91
Weighted-average number of common shares outstanding:
Basic (in shares)	365.0	373.9	368.4	376.2
Diluted (in shares)	368.0	376.8	370.9	378.7