Annual report pursuant to Section 13 and 15(d)

CASH AND INVESTMENTS - Changes in Level 3 Instruments Measured on a Recurring Basis (Detail)

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CASH AND INVESTMENTS - Changes in Level 3 Instruments Measured on a Recurring Basis (Detail) (USD $)
In Millions, unless otherwise specified
12 Months Ended
Dec. 31, 2012
Dec. 31, 2011
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Beginning Balance $ 217 $ 405
Transfers into (out of) Level 3 0 0
Net realized and unrealized gains (losses):    
Included in earnings (in investment income) (54) (50)
Included in accumulated other comprehensive income (pre-tax) 0 0
Purchases 0 0
Settlements 0 (138)
Ending Balance 163 217
Marketable securities
   
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Beginning Balance 0 138
Transfers into (out of) Level 3 0 0
Net realized and unrealized gains (losses):    
Included in earnings (in investment income) 0 0
Included in accumulated other comprehensive income (pre-tax) 0 0
Purchases 0 0
Settlements 0 (138)
Ending Balance 0 0
Other Long-term Investments
   
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Beginning Balance 217 267
Transfers into (out of) Level 3 0 0
Net realized and unrealized gains (losses):    
Included in earnings (in investment income) (54) (50)
Included in accumulated other comprehensive income (pre-tax) 0 0
Purchases 0 0
Settlements 0 0
Ending Balance $ 163 $ 217