Goodwill and Acquired Intangible Assets - Acquired Intangible Assets (Parenthetical) (Detail) (Trade Names and Trademarks [Member], USD $) In Millions, unless otherwise specified	Dec. 31, 2012
Trade Names and Trademarks [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Intangible assets not subject to amortization, net	$ 10

Amount of assets, excluding financial assets and goodwill, lacking physical substance and having a projected indefinite period of benefit.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 30

-Section 50

-Paragraph 2

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=26713463&loc=d3e16323-109275

Name:	us-gaap_IndefiniteLivedIntangibleAssetsExcludingGoodwill
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant