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		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Schedule of Investments [Line Items]
Total income from financial investments		$ 2	$ 8	$ 20
Private Equity Funds [Member]
Schedule of Investments [Line Items]
Realized gains from private equity funds		2	7	20
Income from other investments, net			1
Impairment charges - private equity funds				$ (2)