v2.4.0.6
Related-party Transactions - Schedule of Amounts Related to Revenue and Expenses Incurred in Transactions (Detail) (USD $)
In Millions, unless otherwise specified
12 Months Ended
Dec. 31, 2012
Dec. 31, 2011
Dec. 31, 2010
Related Party Transaction [Line Items]      
Revenue $ 33 $ 133 $ 292
Purchase of goods and services $ 204 $ 137 $ 139