Quarterly report pursuant to Section 13 or 15(d)

Debt Outstanding (Parenthetical) (Detail)

v2.4.0.6
Debt Outstanding (Parenthetical) (Detail)
Sep. 30, 2012
Dec. 31, 2011
Notes, 7.34%, due in installments through May 2014 [Member]
   
Debt Outstanding [Line Items]    
Debt, interest rate 7.34% 7.34%
Debt, maturity date 2014-05 2014-05
Notes, 4.45%, due December 2014 [Member]
   
Debt Outstanding [Line Items]    
Debt, interest rate 4.45% 4.45%
Debt, maturity date 2014-12 2014-12
Notes, 6.30%, due July 2017 [Member]
   
Debt Outstanding [Line Items]    
Debt, interest rate 6.30% 6.30%
Debt, maturity date 2017-07 2017-07
Debentures, 6.90%, Due July 2028 [Member]
   
Debt Outstanding [Line Items]    
Debt, interest rate 6.90% 6.90%
Debt, maturity date 2028-07 2028-07
Notes, 7.00%, Due July 2037 [Member]
   
Debt Outstanding [Line Items]    
Debt, interest rate 7.00% 7.00%
Debt, maturity date 2037-07 2037-07