Quarterly report pursuant to Section 13 or 15(d)

Available-for-sale investments - Additional Information (Detail)

v2.3.0.15
Available-for-sale investments - Additional Information (Detail) (Level 1 Input, USD $)
In Millions
Sep. 30, 2011
Level 1 Input
 
Schedule of Available-for-sale Securities [Line Items]  
Available-for-sale securities, fair value $ 203