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		390.9
Balance at Dec. 31, 2020	$ 2,943.9		$ 39.0	$ 1,099.3	$ 2,636.9	$ (880.2)		$ 2,895.0	$ 48.9
Net income	604.8
Net income available to IPG common stockholders	594.9				594.9			594.9
Net income attributable to noncontrolling interest	9.9								9.9
Other comprehensive loss	(49.1)					(48.2)		(48.2)
Other comprehensive loss, attributable to noncontrolling interest									(0.9)
Reclassifications related to redeemable noncontrolling interests	(0.1)								(0.1)
Distributions to noncontrolling interests	(9.0)								9.0
Change in redemption value of redeemable noncontrolling interests	(2.1)				(2.1)			(2.1)
Repurchases of Common Stock	0.0
Common stock dividends	(320.8)				(320.8)			(320.8)
Stock-based compensation, shares		3.0
Stock-based compensation, value	69.2		0.3	68.9				69.2
Exercise of stock options, shares		0.6
Exercise of stock options, value	8.6		0.1	8.5				8.6
Shares withheld for taxes, shares		(0.9)
Shares withheld for taxes, value	(25.2)		0.1	25.1				25.2
Other	(0.9)								(0.9)
Balance at Sep. 30, 2021	3,221.3		39.3	1,151.6	2,908.9	(928.4)		3,171.4	49.9
Common Stock, shares		393.5
Balance at Jun. 30, 2021	3,111.3		39.3	1,132.4	2,777.5	(886.3)		3,062.9	48.4
Net income	244.6
Net income available to IPG common stockholders	239.9				239.9			239.9
Net income attributable to noncontrolling interest	4.7								4.7
Other comprehensive loss	(43.0)					(42.1)		(42.1)
Other comprehensive loss, attributable to noncontrolling interest									(0.9)
Reclassifications related to redeemable noncontrolling interests	0.5								0.5
Distributions to noncontrolling interests	(2.2)								2.2
Change in redemption value of redeemable noncontrolling interests	(1.4)				(1.4)			(1.4)
Common stock dividends	(107.1)				(107.1)			(107.1)
Stock-based compensation, shares		0.1
Stock-based compensation, value	19.8		0.0	19.8				19.8
Exercise of stock options, shares		0.0
Exercise of stock options, value	0.2		0.0	0.2				0.2
Shares withheld for taxes, shares		0.0
Shares withheld for taxes, value	(0.8)		(0.0)	0.8				0.8
Other	(0.4)								(0.4)
Balance at Sep. 30, 2021	3,221.3		39.3	1,151.6	2,908.9	(928.4)		3,171.4	49.9
Common Stock, shares		393.6
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	(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)							(0.0)	4.4
Change in redemption value of redeemable noncontrolling interests	0.1				0.1			0.1
Repurchases 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		0.0	17.4				17.4
Shares withheld for taxes, shares		0.0
Shares withheld for taxes, value	(0.2)		(0.0)	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