Quarterly report pursuant to Section 13 or 15(d)

Activity Related to Noncontrolling Interests (Detail)

v2.4.0.6
Activity Related to Noncontrolling Interests (Detail) (USD $)
In Millions, unless otherwise specified
3 Months Ended
Mar. 31, 2013
Mar. 31, 2012
Dec. 31, 2012
Stockholders' Equity Attributable to Noncontrolling Interest [Roll Forward]      
Balance at beginning of period   $ 73 $ 80
Acquired noncontrolling interests (65) 3  
Dividends attributable to noncontrolling interests 0 0  
Net income attributable to noncontrolling interests 0 0  
Balance at end of period $ 15 $ 76 $ 80