Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Statement of Comprehensive Income [Abstract]
NET INCOME	$ 972.8	$ 354.2	$ 673.9
Foreign Currency Translation:
Foreign currency translation adjustments	(86.1)	39.4	11.3
Reclassification adjustments recognized in net income	(1.0)	20.0	6.7
Foreign currency translation, net of tax	(87.1)	59.4	18.0
Derivatives instruments:
Changes in fair value of derivative instruments	14.0	11.3	0.0
Recognition of previously unrealized losses included in net income	4.2	2.4	2.3
Income tax effect	(2.1)	(3.4)	(0.5)
Derivative instruments, net of tax	16.1	10.3	1.8
Defined benefit pension and other postretirement plans:
Net actuarial gains (losses) for the period	58.0	(29.2)	(14.8)
Other Comprehensive (Income) Loss, Defined Benefit Plan, Reclassification Adjustment from AOCI, before Tax	9.4	7.4	6.7
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Settlement and Curtailment	0.6	(0.1)	0.0
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Other, before Tax	1.3	(3.3)	(2.5)
Income tax effect	(13.8)	4.6	1.2
Defined benefit pension and other postretirement plans, net of tax	55.5	(20.6)	(9.4)
Other comprehensive (loss) income, net of tax	(15.5)	49.1	10.4
Total comprehensive income	957.3	403.3	684.3
Less: comprehensive income attributable to noncontrolling interests	18.5	2.4	17.2
Comprehensive Income Attributable to IPG	$ 938.8	$ 400.9	$ 667.1