Business Acquisitions - Finite-Lived Intangible Assets Acquired as Part of Business Combination (Detail) (Arbitron, USD $) In Millions, unless otherwise specified	9 Months Ended
	Sep. 30, 2013
Acquired Finite Lived Intangible Assets [Line Items]
Provisional allocation of purchase price to identified intangible assets	$ 517
Customer –related intangibles
Acquired Finite Lived Intangible Assets [Line Items]
Provisional allocation of purchase price to identified intangible assets	323
Customer –related intangibles | Minimum
Acquired Finite Lived Intangible Assets [Line Items]
Finite lived intangible assets useful life	10 years
Customer –related intangibles | Maximum
Acquired Finite Lived Intangible Assets [Line Items]
Finite lived intangible assets useful life	20 years
Computer software
Acquired Finite Lived Intangible Assets [Line Items]
Provisional allocation of purchase price to identified intangible assets	150
Computer software | Minimum
Acquired Finite Lived Intangible Assets [Line Items]
Finite lived intangible assets useful life	5 years
Computer software | Maximum
Acquired Finite Lived Intangible Assets [Line Items]
Finite lived intangible assets useful life	10 years
Trade names and trademarks
Acquired Finite Lived Intangible Assets [Line Items]
Provisional allocation of purchase price to identified intangible assets	33
Trade names and trademarks | Maximum
Acquired Finite Lived Intangible Assets [Line Items]
Finite lived intangible assets useful life	5 years
Covenants-not-to-compete
Acquired Finite Lived Intangible Assets [Line Items]
Provisional allocation of purchase price to identified intangible assets	$ 11
Covenants-not-to-compete | Minimum
Acquired Finite Lived Intangible Assets [Line Items]
Finite lived intangible assets useful life	1 year
Covenants-not-to-compete | Maximum
Acquired Finite Lived Intangible Assets [Line Items]
Finite lived intangible assets useful life	2 years