Goodwill and Other Intangible Assets (Tables)

3 Months Ended

12 Months Ended

Mar. 31, 2013

Dec. 31, 2012

Goodwill And Intangible Assets Disclosure [Abstract]

Summary of Changes in Carrying Amount of Goodwill

The table below summarizes the changes in the carrying amount of goodwill by reportable segment for the three months ended March 31, 2013.

(IN MILLIONS)	Buy			Watch			Expositions		Total
Balance, December 31, 2012	$	3,126		$	3,661		$	565	$	7,352
Acquisitions, divestitures and other adjustments		4			1			—		5
Effect of foreign currency translation		(34	)		(1	)		—		(35	)
Balance, March 31, 2013	$	3,096		$	3,661		$	565	$	7,322

The table below summarizes the changes in the carrying amount of goodwill by reportable segment for the years ended December 31, 2012 and 2011, respectively.

(IN MILLIONS)	Buy			Watch			Expositions		Total
Balance December 31, 2010	$	2,990		$	3,546		$	560	$	7,096
Acquisitions, divestitures and other adjustments		123			—			—		123
Effect of foreign currency translation		(58	)		(6	)		—		(64	)
Balance December 31, 2011	$	3,055		$	3,540		$	560	$	7,155
Acquisitions, divestitures and other adjustments		14			117			5		136
Effect of foreign currency translation		57			4			—		61
Balance December 31, 2012	$	3,126		$	3,661		$	565	$	7,352
Cumulative Impairments	$	—		$	376		$	2	$	378

Other Intangible Assets

Other Intangible Assets

(IN MILLIONS)	Gross Amounts				Accumulated Amortization
	March 31, 2013		December 31, 2012		March 31, 2013			December 31, 2012
Indefinite-lived intangibles:
Trade names and trademarks	$	1,921	$	1,921	$	—		$	—
Amortized intangibles:
Trade names and trademarks	$	126	$	128	$	(48	)	$	(46	)
Customer-related intangibles		2,882		2,882		(922	)		(886	)
Covenants-not-to-compete		36		36		(26	)		(25	)
Computer software		1,360		1,316		(843	)		(804	)
Patents and other		93		90		(60	)		(57	)
Total	$	4,497	$	4,452	$	(1,899	)	$	(1,818	)

Other Intangible Assets

(IN MILLIONS)	Gross Amounts				Accumulated Amortization
	December 31, 2012		December 31, 2011		December 31, 2012			December 31, 2011
Indefinite-lived intangibles:
Trade names and trademarks	$	1,921	$	1,921	$	—		$	—
Amortized intangibles:
Trade names and trademarks	$	128	$	113	$	(46	)	$	(37	)
Customer-related intangibles		2,882		2,823		(886	)		(747	)
Covenants-not-to-compete		36		32		(25	)		(22	)
Computer software		1,316		1,089		(804	)		(648	)
Patents and other		90		83		(57	)		(46	)
Total	$	4,452	$	4,140	$	(1,818	)	$	(1,500	)

Summary of Estimated Future Amortization Expense

All other intangible assets are subject to amortization. Future amortization expense is estimated to be as follows:

(IN MILLIONS)
For the year ending December 31:
2013	$	330
2014		303
2015		269
2016		194
2017		165
Thereafter		1,373
Total	$	2,634