Fair Value of Financial Investments and Liabilities - Income from Financial Investments Net, Included in Other, Net, Within Other Income (Expense), Net (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Schedule of Investments [Line Items]
Total income from financial investments	$ 5	$ 2	$ 8	$ 18
Private Equity Funds [Member]
Schedule of Investments [Line Items]
Realized gains from private equity funds	4	2	7	18
Income from other investments, net	1		1
Impairment charges - private equity funds		$ (2)		$ (2)