Business Acquisitions - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	9 Months Ended		3 Months Ended	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2013 Arbitron	Sep. 30, 2013 Arbitron
Business Acquisition [Line Items]
Business acquisition purchase price				$ 1,300
Percentage ownership interest acquired			100.00%	100.00%
Acquisition Date				Sep. 30, 2013
Acquisition related expenses			4	18
Net of cash paid for acquisitions	$ 203	$ 42