Long-Term Debt - Additional Information (Detail) (USD $)	9 Months Ended
	Sep. 30, 2013	Dec. 31, 2012	Nov. 30, 2012 tranch
Debt Instrument [Line Items]
Carrying amount of other long term debt including current portion	$ 747,000,000	$ 691,000,000
Senior Notes
Debt Instrument [Line Items]
Face amount			3,000,000,000
Number of tranches of debt issued			3
Unamortized discount	24,000,000	27,000,000
Interest payment frequency	semi-annually in arrears in May and November
Total estimated fair value of notes	$ 2,900,000,000	$ 3,000,000,000
0.65% Notes due on November 27, 2015
Debt Instrument [Line Items]
Effective interest yields	0.84%
1.20% Notes due on November 29, 2017
Debt Instrument [Line Items]
Effective interest yields	1.38%
2.50% Notes due on November 29, 2022
Debt Instrument [Line Items]
Effective interest yields	2.66%
Other Long Term Debt
Debt Instrument [Line Items]
Long-term debt, weighted average interest rate	6.30%	6.40%