v2.4.0.6
Provision for Income Taxes - Reconciliation of Unrecognized Tax Benefits (Detail) (USD $)
In Millions, unless otherwise specified
12 Months Ended
Dec. 31, 2012
Dec. 31, 2011
Dec. 31, 2010
Income Tax Disclosure [Line Items]      
Balance as of January 1, $ 169 $ 195 $ 52
Increases from tax positions taken during prior periods 16   10
Decreases from tax positions taken during prior periods (25) (12) (7)
Increases from tax positions taken during current period 2 10 140
Decreases relating to settlements with the tax authorities (23) (24)  
Balance as of December 31, $ 139 $ 169 $ 195