Stock-Based Compensation - Schedule of Options Outstanding (Parenthetical) (Detail) (USD $) In Millions, except Share data, unless otherwise specified	12 Months Ended
Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total intrinsic value of options exercised	$ 56	$ 6	$ 19
Stock Option Holder [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercised number of shares, under stock option plan	849,999	1,100,001	1,283,334
Cash payments made on cashless exercise of stock options	$ 23	$ 19	$ 30

Amount of accumulated difference between fair value of underlying shares on dates of exercise and exercise price on options exercised (or share units converted) into shares.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (d)(2)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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