v2.4.0.6
CONSOLIDATED BALANCE SHEETS (Parenthetical) (USD $)
In Millions, except Share data, unless otherwise specified
Dec. 31, 2011
Dec. 31, 2010
Trade accounts receivable, allowance (in dollars) $ 113 $ 177
Common shares, par value (in dollars per share) $ 0.01 $ 0.01
Common shares, authorized 400,000,000 400,000,000
Common shares, issued 145,610,029 146,635,083
Common shares outstanding 145,610,029 146,635,083
Treasury shares 1,933,286  
Convertible perpetual preference shares
   
Preference shares, par value (in dollars per share) $ 0.01 $ 0.01
Preference shares, authorized 6,900,000 6,900,000
Preference shares, issued 6,900,000 6,900,000
Preference shares, outstanding 6,900,000 6,900,000
Preference shares, liquidation preference (in dollars per share) $ 100 $ 100