Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Statement of Comprehensive Income [Abstract]
NET INCOME	$ 632.5	$ 480.5	$ 505.4
Foreign Currency Translation:
Foreign currency translation adjustments	(55.9)	(256.8)	(194.3)
Less: reclassification adjustments recognized in net income	3.7	23.3	(0.9)
Foreign currency translation, net of tax	(52.2)	(233.5)	(195.2)
Available-for-sale securities:
Changes in fair value of available-for-sale securities	0.5	0.5	0.7
Less: recognition of previously unrealized gains included in net income	(1.3)	0.0	0.0
Income tax effect	0.1	0.0	(0.3)
Available-for-sale securities, net of tax	(0.7)	0.5	0.4
Derivatives instruments:
Changes in fair value of derivative instruments	0.0	0.0	(0.6)
Less: recognition of previously unrealized losses included in net income	2.0	2.0	1.9
Income tax effect	(0.8)	(0.7)	(0.5)
Derivative instruments, net of tax	1.2	1.3	0.8
Defined benefit pension and other postretirement plans:
Net actuarial (losses) gains for the period	(85.4)	14.2	(55.5)
Less: amortization of unrecognized losses, transition obligation and prior service cost included in net income	5.4	10.6	10.0
Less: settlement and curtailment losses (gains) included in net income	0.4	(0.2)	0.5
Other	(2.0)	0.4	0.5
Income tax effect	15.3	(6.4)	10.4
Defined benefit pension and other postretirement plans, net of tax	(66.3)	18.6	(34.1)
Other comprehensive loss, net of tax	(118.0)	(213.1)	(228.1)
Total comprehensive income	514.5	267.4	277.3
Less: comprehensive income attributable to noncontrolling interest	22.9	21.7	25.7
Comprehensive Income Attributable to IPG	$ 491.6	$ 245.7	$ 251.6