Quarterly report pursuant to Section 13 or 15(d)

CASH AND INVESTMENTS - Additional Information (Detail)

v2.4.0.6
CASH AND INVESTMENTS - Additional Information (Detail) (USD $)
In Millions, unless otherwise specified
3 Months Ended 12 Months Ended
Mar. 31, 2013
Dec. 31, 2012
Gain (Loss) on Investments [Line Items]    
Restricted Cash and Investments, Noncurrent $ 406 $ 307
Fair Value Inputs, Discount Rate 8.08% 7.75%
Self-insurance requirements [Member]
   
Gain (Loss) on Investments [Line Items]    
Restricted Cash and Investments, Noncurrent 387 288
Variable life insurance policy
   
Gain (Loss) on Investments [Line Items]    
Restricted Cash and Investments, Noncurrent $ 19 $ 19