Discontinued Operations - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	9 Months Ended
Sep. 30, 2013
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Stock purchase agreement	100.00%
Aggregate purchase price	$ 11
Scenario, Forecast [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Recognized gain, net of tax	$ 7

Amount of gain (loss), after tax expense or benefit and not previously recognized, resulting from the sale of a business component.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 205

-SubTopic 20

-Section 45

-Paragraph 3

-URI http://asc.fasb.org/extlink&oid=6892542&loc=d3e957-107759

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 205

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=6360339&loc=d3e1361-107760

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration