Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Statement of Comprehensive Income [Abstract]
NET INCOME	$ 113.6	$ 132.1
Foreign currency translation:
Foreign currency translation adjustments	(52.3)	22.3
Foreign currency transaction and translation adjustment, net of tax	(52.3)	22.3
Derivative Instrument:
Changes in fair value of derivative instruments	0.0	(2.8)
Recognition of previously unrealized gain in net income	(0.9)	(0.4)
Income tax effect	0.2	0.8
Net unrecognized gains on derivative instruments, net of tax	(0.7)	(2.4)
Defined benefit pension and other postretirement plans:
Net actuarial gains for the period	0.8	1.9
Amortization of unrecognized losses, transition obligation and prior service cost included in net income	1.9	1.7
Other	0.1	0.4
Income tax effect	(0.5)	(0.4)
Defined benefit pension and other postretirement plans adjustment, net of tax	2.3	3.6
Other comprehensive loss, net of tax	(50.7)	23.5
TOTAL COMPREHENSIVE INCOME	62.9	155.6
Less: comprehensive income attributable to noncontrolling interests	2.0	5.8
COMPREHENSIVE INCOME ATTRIBUTABLE TO IPG	$ 60.9	$ 149.8