Consolidated Statements of Comprehensive Income (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Statement of Other Comprehensive Income [Abstract]
NET INCOME	$ 105.5	$ 108.9	$ 59.8	$ 55.7
OTHER COMPREHENSIVE INCOME
Foreign currency translation adjustments	(66.3)	22.3	(21.2)	66.0
Available-for-sale securities:
Changes in market value of available-for sale securities	135.0	0.1	135.5	0.7
Less: recognition of previously unrealized losses included in net income	0	0.2	0.6	0.2
Available-for-sale securities, Income tax effect	(50.6)	0	(50.6)	(0.1)
Available-for-sale securities, Net of tax	84.4	0.3	85.5	0.8
Derivative instruments:
Changes in fair value of derivative instruments	(15.8)	0	(18.6)	0
Derivative instruments, Income tax effect	7.7	0	7.7	0
Derivative instruments, Net of tax	(8.1)	0	(10.9)	0
Defined benefit pension and other postretirement plans:
Net actuarial gains for the period	1.3	3.7	1.0	3.7
Less: amortization of unrecognized losses, transition obligation and prior service cost included in net income	1.8	1.9	3.7	3.8
Other	0	(0.1)	(0.1)	(0.1)
Defined benefit pension and other postretirement plans, Income tax effect	(1.2)	(0.7)	(1.7)	(1.4)
Defined benefit pension and other postretirement plans, Net of tax	1.9	4.8	2.9	6.0
Other comprehensive income, Net of tax	11.9	27.4	56.3	72.8
Total Comprehensive Income	117.4	136.3	116.1	128.5
Less: comprehensive income (loss) attributable to noncontrolling interest	2.0	4.5	(0.2)	(3.3)
Comprehensive Income Attributable to IPG	$ 115.4	$ 131.8	$ 116.3	$ 131.8