Consolidated Statements of Comprehensive Income - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Statement of Comprehensive Income [Abstract]
NET INCOME		$ 132.7	$ 78.0	$ 295.6	$ 197.6
Foreign currency translation:
Foreign currency translation adjustments		4.4	(109.0)	43.5	(218.0)
Less: reclassification adjustments recognized in net income	[1]	(4.2)	14.9	2.3	13.7
Foreign currency transaction and translation adjustment, net of tax		0.2	(94.1)	45.8	(204.3)
Available-for-sale securities:
Changes in fair value of available-for sale securities		0.2	0.2	0.4	0.4
Less: recognition of previously unrealized gains included in net income		(0.1)	0.0	(1.3)	0.0
Income tax effect		0.1	0.0	0.1	(0.1)
Net unrealized gains/losses on available-for-sale securities, net of tax		0.2	0.2	(0.8)	0.3
Derivative instruments:
Recognition of previously unrealized losses in net income		0.5	0.5	1.5	1.5
Income tax effect		(0.2)	(0.7)	(0.6)	(1.1)
Net unrecognized gains/losses on derivative instruments, net of tax		0.3	(0.2)	0.9	0.4
Defined benefit pension and other postretirement plans:
Net actuarial (losses) gains for the period		(79.2)	2.8	(78.4)	8.5
Less: amortization of unrecognized losses, transition obligation and prior service cost included in net income		1.2	1.3	3.7	7.5
Less: settlement and curtailment losses (gains) included in net income		0.1	(0.2)	0.3	0.0
Other		0.0	0.1	0.0	(0.1)
Income tax effect		13.0	(2.6)	12.5	(4.8)
Defined benefit pension and other postretirement plans adjustment, net of tax		(64.9)	1.4	(61.9)	11.1
Other comprehensive loss, net of tax		(64.2)	(92.7)	(16.0)	(192.5)
TOTAL COMPREHENSIVE INCOME (LOSS)		68.5	(14.7)	279.6	5.1
Less: comprehensive income attributable to noncontrolling interests		5.4	0.8	5.9	0.3
COMPREHENSIVE INCOME (LOSS) ATTRIBUTABLE TO IPG		$ 63.1	$ (15.5)	$ 273.7	$ 4.8

[1] These foreign currency translation adjustments are primarily a result of the sales of businesses