Consolidated Statements of Stockholders' Equity - USD ($) shares in Millions, $ in Millions	Total	Common Stock, Shares	Common Stock, Amount	Additional Paid-In Capital	Retained Earnings	Accumulated Other Comprehensive Loss, Net of Tax	Treasury Stock [Member]	Total IPG Stockholders' Equity	Noncontrolling Interests
Common Stock, shares		394.3
Balance at Dec. 31, 2021	$ 3,589.2		$ 39.3	$ 1,226.6	$ 3,154.3	$ (894.2)	$ 0.0	$ 3,526.0	$ 63.2
Net income	650.2
Net income available to IPG common stockholders	640.8				640.8			640.8
Net income attributable to noncontrolling interest	9.4								9.4
Other comprehensive loss	(210.1)					(208.4)		(208.4)
Other comprehensive loss, attributable to noncontrolling interest									(1.7)
Reclassifications related to redeemable noncontrolling interests	2.3			3.1				3.1	(0.8)
Distributions to noncontrolling interests	(9.6)								9.6
Change in redemption value of redeemable noncontrolling interests	(1.2)				(1.2)			(1.2)
Repurchases of common stock including excise tax	(221.6)
Payments for Repurchase of Common Stock	(221.6)						221.6	221.6
Common stock dividends	(344.0)				(344.0)			(344.0)
Stock-based compensation, shares		3.3
Stock-based compensation, value	54.0		0.4	53.6				54.0
Shares withheld for taxes, shares		(1.0)
Shares withheld for taxes, value	(38.4)		0.1	38.3				38.4
Other	9.1			(0.5)				0.5	9.6
Balance at Sep. 30, 2022	3,457.1		39.6	1,239.3	3,449.9	(1,102.6)	(221.6)	3,404.6	52.5
Common Stock, shares		396.4
Balance at Jun. 30, 2022	3,489.0		39.6	1,222.1	3,311.8	(988.9)	(147.9)	3,436.7	52.3
Net income	257.5
Net income available to IPG common stockholders	251.8				251.8			251.8
Net income attributable to noncontrolling interest	5.7								5.7
Other comprehensive loss	(114.4)					(113.7)		(113.7)
Other comprehensive loss, attributable to noncontrolling interest									(0.7)
Reclassifications related to redeemable noncontrolling interests	(0.0)			(0.0)				(0.0)	(0.0)
Distributions to noncontrolling interests	(4.4)								4.4
Change in redemption value of redeemable noncontrolling interests	0.1				0.1			0.1
Payments for Repurchase of Common Stock	(73.7)						73.7	73.7
Common stock dividends	(113.8)				(113.8)			(113.8)
Stock-based compensation, shares		0.2
Stock-based compensation, value	17.4			17.4				17.4
Shares withheld for taxes, value	(0.2)			0.2				0.2
Other	0.4								0.4
Balance at Sep. 30, 2022	3,457.1		39.6	1,239.3	3,449.9	(1,102.6)	(221.6)	3,404.6	52.5
Common Stock, shares		396.6
Common Stock, shares		389.6
Balance at Dec. 31, 2022	3,706.0		38.9	1,057.5	3,632.1	(960.4)	(120.2)	3,647.9	58.1
Net income	646.5
Net income available to IPG common stockholders	635.2				635.2			635.2
Net income attributable to noncontrolling interest	11.3								11.3
Other comprehensive loss	(22.6)					(22.1)		(22.1)
Other comprehensive loss, attributable to noncontrolling interest									(0.5)
Reclassifications related to redeemable noncontrolling interests	(0.2)								(0.2)
Distributions to noncontrolling interests	(13.7)								13.7
Change in redemption value of redeemable noncontrolling interests	3.7				3.7			3.7
Repurchase of common stock including excise tax	(220.2)
Payments for Repurchase of Common Stock	(219.0)						220.2	220.2
Common stock dividends	(359.9)				(359.9)			(359.9)
Stock-based compensation, shares		4.2
Stock-based compensation, value	54.6		0.4	54.2				54.6
Shares withheld for taxes, shares		(1.6)
Shares withheld for taxes, value	(59.0)		0.1	58.9				59.0
Other	0.7								(0.7)
Balance at Sep. 30, 2023	3,736.3		39.2	1,052.8	3,911.1	(982.5)	(340.4)	3,680.2	56.1
Common Stock, shares		392.0
Balance at Jun. 30, 2023	3,745.8		39.2	1,035.2	3,782.8	(922.7)	(248.2)	3,686.3	59.5
Net income	245.7
Net income available to IPG common stockholders	243.7				243.7			243.7
Net income attributable to noncontrolling interest	2.0								2.0
Other comprehensive loss	(60.1)					(59.8)		(59.8)
Other comprehensive loss, attributable to noncontrolling interest									(0.3)
Reclassifications related to redeemable noncontrolling interests	(0.1)								(0.1)
Distributions to noncontrolling interests	(5.2)								5.2
Change in redemption value of redeemable noncontrolling interests	3.7				3.7			3.7
Payments for Repurchase of Common Stock	(92.2)						92.2	92.2
Common stock dividends	(119.1)				(119.1)			(119.1)
Stock-based compensation, shares		0.2
Stock-based compensation, value	17.8		0.0	17.8				17.8
Shares withheld for taxes, shares		(0.0)
Shares withheld for taxes, value	(0.2)		0.0	0.2				0.2
Other	0.0								(0.0)
Balance at Sep. 30, 2023	$ 3,736.3		$ 39.2	$ 1,052.8	$ 3,911.1	$ (982.5)	$ (340.4)	$ 3,680.2	$ 56.1
Common Stock, shares		392.2