v2.4.0.6
Reconciliation of Tax Contingencies (Detail) (USD $)
In Millions, unless otherwise specified
 12 Months Ended
Dec. 31, 2012
Dec. 31, 2011
Dec. 31, 2010
Income Tax Contingency [Line Items]      
Beginning balance $ 229 [1] $ 213 [1] $ 181
Gross increases to tax positions in prior periods 91 22 31
Gross decreases to tax positions in prior periods (47) (3) (1)
Gross increases to current period tax positions 26 4 5
Audit settlements paid during 2012 (4) (1) (3)
Lapse of statute of limitations (1) (6)  
Ending balance $ 294 [1] $ 229 [1] $ 213 [1]
[1] As of December 31, 2012, we had $294 million of tax contingencies all of which, if fully recognized, would decrease our effective tax rate.