v2.4.0.8
Schedule of Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) (Fair Value, Measurements, Recurring, USD $)
In Millions, unless otherwise specified
Dec. 31, 2013
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]  
Fair value of assets measured on a recurring basis $ 10,908
Fair value of liabilities measured on a recurring basis 23
Cash and Cash Equivalents | Fixed Income Securities
  
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]  
Fair value of assets measured on a recurring basis 9,190
Short-term Investments | Fixed Income Securities
  
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]  
Fair value of assets measured on a recurring basis 214
Short-term Investments | Equity Securities
  
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]  
Fair value of assets measured on a recurring basis 387
Other Assets | Fixed Income Securities
  
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]  
Fair value of assets measured on a recurring basis 875
Other Assets | Forward Interest Rate Swaps
  
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]  
Fair value of assets measured on a recurring basis 76
Other Assets | Cross Currency Swaps
  
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]  
Fair value of assets measured on a recurring basis 166
Other Liabilities | Interest Rate Swaps
  
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]  
Fair value of liabilities measured on a recurring basis 23
Level 1
  
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]  
Fair value of assets measured on a recurring basis 9,580 [1]
Level 1 | Cash and Cash Equivalents | Fixed Income Securities
  
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]  
Fair value of assets measured on a recurring basis 9,190 [1]
Level 1 | Short-term Investments | Fixed Income Securities
  
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]  
Fair value of assets measured on a recurring basis 3 [1]
Level 1 | Short-term Investments | Equity Securities
  
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]  
Fair value of assets measured on a recurring basis 387 [1]
Level 2
  
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]  
Fair value of assets measured on a recurring basis 1,328 [2]
Fair value of liabilities measured on a recurring basis 23 [2]
Level 2 | Short-term Investments | Fixed Income Securities
  
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]  
Fair value of assets measured on a recurring basis 211 [2]
Level 2 | Other Assets | Fixed Income Securities
  
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]  
Fair value of assets measured on a recurring basis 875 [2]
Level 2 | Other Assets | Forward Interest Rate Swaps
  
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]  
Fair value of assets measured on a recurring basis 76 [2]
Level 2 | Other Assets | Cross Currency Swaps
  
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]  
Fair value of assets measured on a recurring basis 166 [2]
Level 2 | Other Liabilities | Interest Rate Swaps
  
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]  
Fair value of liabilities measured on a recurring basis $ 23 [2]
[1] quoted prices in active markets for identical assets or liabilities
[2] observable inputs other than quoted prices in active markets for identical assets and liabilities