v2.4.0.6
Related-party Transactions - Schedule of Amounts Related to Accounts Receivable and Payable Balances with Related Parties (Detail) (USD $)
In Millions, unless otherwise specified
Dec. 31, 2012
Dec. 31, 2011
Related Party Transaction [Line Items]    
Receivables (net)   $ 20
Payables $ 30 $ 38