Valuation and Qualifying Accounts (Detail) (Allowance for Doubtful Accounts and Sales Credits, USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Allowance for Doubtful Accounts and Sales Credits
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Year	$ 133	$ 101	$ 79
Additions	1,263	214	200
Usage	(815)	(182)	(178)
Balance at End of Year	$ 581	$ 133	$ 101