Consolidated Statements of Stockholders' Equity (USD $) In Millions	Total	Preferred Stock	Common Stock	Additional Paid-In Capital	Retained Earnings	Accumulated Other Comprehensive Loss, Net of Tax	Treasury Stock	Total IPG Stockholders' Equity	Noncontrolling Interests
Beginning balance at Dec. 31, 2011	$ 2,497.3	$ 221.5	$ 48.2	$ 2,427.5	$ 405.1	$ (225.7)	$ (414.9)	$ 2,461.7	$ 35.6
Beginning balance, shares at Dec. 31, 2011			491.4
Net loss	(45.7)				(43.0)			(43.0)	(2.7)
Other comprehensive loss	44.4					43.9		43.9	0.5
Reclassifications related to redeemable noncontrolling interests	16.9			13.0				13.0	3.9
Noncontrolling interest transactions	(0.8)								(0.8)
Distributions to noncontrolling interests	(1.8)								(1.8)
Change in redemption value of redeemable noncontrolling interests	3.3				3.3			3.3
Repurchase of common stock	(52.5)						(52.5)	(52.5)
Common stock dividends	(26.2)				(26.2)			(26.2)
Preferred stock dividends	(2.9)				(2.9)			(2.9)
Stock-based compensation, shares			(0.1)
Stock-based compensation	14.0		0.6	13.4				14.0
Exercise of stock options, shares			0.4
Exercise of stock options	5.0		0.1	4.9				5.0
Shares withheld for taxes, shares			(0.1)
Shares withheld for taxes	(22.7)		(0.2)	(22.5)				(22.7)
Other	(0.2)			0.9	(0.6)			0.3	(0.5)
Ending balance at Mar. 31, 2012	2,428.1	221.5	48.7	2,437.2	335.7	(181.8)	(467.4)	2,393.9	34.2
Ending balance, shares at Mar. 31, 2012			491.6
Beginning balance at Dec. 31, 2012	2,456.6	221.5	48.8	2,465.4	738.3	(288.0)	(765.4)	2,420.6	36.0
Beginning balance, shares at Dec. 31, 2012			492.0
Net loss	(58.5)				(56.3)			(56.3)	(2.2)
Other comprehensive loss	(38.6)					(37.4)		(37.4)	(1.2)
Reclassifications related to redeemable noncontrolling interests	1.7								1.7
Distributions to noncontrolling interests	(1.2)								(1.2)
Change in redemption value of redeemable noncontrolling interests	0.9				0.9			0.9
Repurchase of common stock	(75.8)						(75.8)	(75.8)
Common stock dividends	(31.0)				(31.0)			(31.0)
Preferred stock dividends	(2.9)				(2.9)			(2.9)
Conversion of convertible notes to common stock, shares			16.9
Conversion of convertible notes to common stock	200.0		1.7	198.3				200.0
Capped call transaction	0			10.8			(10.8)	0
Stock-based compensation, shares			0.9
Stock-based compensation	26.8		0.4	26.4				26.8
Exercise of stock options, shares			1.7
Exercise of stock options	18.3		0.2	18.1				18.3
Shares withheld for taxes, shares			(0.1)
Shares withheld for taxes	(19.4)		(0.2)	(19.2)				(19.4)
Other	5.5			5.8	(0.3)			5.5
Ending balance at Mar. 31, 2013	$ 2,482.4	$ 221.5	$ 50.9	$ 2,705.6	$ 648.7	$ (325.4)	$ (852.0)	$ 2,449.3	$ 33.1
Ending balance, shares at Mar. 31, 2013			511.4