v2.4.0.6
Share Based Compensation (Details) (USD $)
In Millions, except Share data, unless otherwise specified
12 Months Ended
Dec. 31, 2010
Dec. 31, 2009
Dec. 31, 2008
Share-Based Compensation      
Aggregate tax benefit (reversal) related to share-based compensation (in dollars)   $ 6 $ (5)
Fair value assumptions      
Expected option term (in years) 5.43 5.14 5.07
Expected dividend yield (as a percent) 1.36% 1.47% 0.60%
Expected volatility (as a percent) 44.34% 43.35% 28.56%
Risk-free interest rate (as a percent) 2.56% 2.31% 2.58%
Options      
Outstanding at the beginning of the period (in shares) 4,658,629    
Granted (in shares) 965,600    
Exercised (in shares) (171,643)    
Forfeited or expired (in shares) (209,755)    
Outstanding at the end of the period (in shares) 5,242,831 4,658,629  
Exercisable at the end of the period (in shares) 3,708,035    
Weighted-Average Exercise Price      
Outstanding at the beginning of the period (in dollars per share) $ 56.32    
Granted (in dollars per share) $ 61.60    
Exercised (in dollars per share) $ 33.00    
Forfeited or expired (in dollars per share) $ 74.52    
Outstanding at the end of the period (in dollars per share) $ 57.34 $ 56.32  
Exercisable at the end of the period (in dollars per share) $ 54.78    
Weighted-Average Remaining Contractual Term      
Outstanding at the end of the period (in years) 5.76    
Exercisable at the end of the period (in years) 4.46    
Aggregate Intrinsic Value      
Outstanding at the end of the period (in dollars) 76    
Exercisable at the end of the period (in dollars) 66    
Weighted-average grant date fair value (in dollars per share) $ 23.70 $ 18.68 $ 31.09
Total intrinsic value of options exercised (in dollars) 4 2 8
Stock Option Awards
     
Share-Based Compensation      
Share-based compensation expense (in dollars) 22 16 16
Restricted Stock Units
     
Share-Based Compensation      
Share-based compensation expense (in dollars) 38 1 50
Restricted Stock Units, Unrecognized Compensation Cost      
Period of recognition of total unrecognized compensation related to non-vested stock options (in years) 2    
Restricted Stock Units      
Restricted stock units outstanding at the beginning of the period (in shares) 1,081,544    
Granted (in shares) 583,753    
Vested/issued (in shares) (348,492)    
Forfeited/cancelled (in shares) (182,052)    
Restricted stock units outstanding at the end of the period (in shares) 1,134,753 1,081,544  
Weighted-Average Grant-Date Fair Value      
Restricted stock units outstanding at the beginning of the period (in dollars per share) $ 75.15    
Granted (in dollars per share) $ 58.67 $ 50.63 $ 110.07
Vested/issued (in dollars per share) $ 80.42    
Forfeited/cancelled (in dollars per share) $ 65.78    
Restricted stock units outstanding at the end of the period (in dollars per share) $ 67.15 $ 75.15  
Restricted Stock Units, Additional Activity Information      
Unvested corresponding dividends accrued (in shares) 14,888    
Common shares issued, net of common shares withheld to cover taxes (in shares) 348,492    
Common shares issued, net of common shares withheld to cover taxes, weighted-average fair value (in dollars per share) $ 60.39    
Payment/issuance deferred during period, vested restricted stock units and earned dividends (in shares) 4,340    
Deferred common share units including common shares representing accrued corresponding dividends, as of period end 24,003    
Shares cancelled related to performance-based restricted stock unit awards (in shares) 167,348    
Total fair value of restricted stock units vested (in dollars) 28    
2009 Equity Incentive Plan and Equity Incentive Plan | Stock Option Awards
     
Share-Based Compensation      
Expiration period of award (in years) 10 years    
Vesting period (in years) 3Y    
2009 Equity Incentive Plan and Equity Incentive Plan | Performance-based restricted stock units
     
Share-Based Compensation      
Vesting period (in years) 3Y    
Performance period (in years) 3Y    
Percentage of award vested if minimum performance target is achieved (as a percent) 50.00%    
Capped percentage of award vested if maximum performance target is achieved (as a percent) 200.00%    
2009 Equity Incentive Plan and Equity Incentive Plan | Time-vested restricted stock units
     
Share-Based Compensation      
Vesting period, low end of the range (in years) 3    
Vesting period, high end of the range (in years) 5    
Percentage of units vested (percentage, expressed as a decimal) 100%    
2009 EIP
     
Common Shares Reserved for Share-Based Awards      
Common shares reserved for grant of stock options, stock awards and other awards (in shares) 10,000,000    
Common shares available for future grants (in shares) 8,554,697    
2009 EIP | Restricted Stock Units
     
Restricted Stock Units, Unrecognized Compensation Cost      
Total unrecognized compensation related to non-vested awards (in dollars) 36    
Equity Incentive Plan | Stock Option Awards
     
Restricted Stock Units, Unrecognized Compensation Cost      
Total unrecognized compensation related to non-vested awards (in dollars) $ 21    
Period of recognition of total unrecognized compensation related to non-vested stock options (in years) 2    
2007 Directors' Plan
     
Common Shares Reserved for Share-Based Awards      
Common shares reserved for grant of stock options, stock awards and other awards (in shares) 600,000    
Common shares available for future grants (in shares) 453,775    
2007 Directors' Plan | Stock Option Awards
     
Share-Based Compensation      
Expiration period of award (in years) 10 years    
Vesting period (in years) third anniversary    
2007 Directors' Plan | Restricted Stock Units
     
Share-Based Compensation      
Vesting period (in years) third anniversary    
2007 Directors' Plan | Deferred restricted stock units
     
Share-Based Compensation      
Vesting period (in years) first anniversary    
Period of payment deferral (in years) third anniversary