v2.4.0.8
Stock-Based Compensation (Schedule of Non-qualified Stock Option Activity) (Details) (USD $)
In Millions, except Share data, unless otherwise specified
 9 Months Ended 12 Months Ended
Sep. 30, 2013
Dec. 31, 2012
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]    
Options, Outstanding 14,226,669 17,862,501
Options, Outstanding, Weighted Average Exercise Price $ 18.21 $ 17.30
Options, Outstanding, Weighted Average Remaining Contractual Term 3 years 4 months 26 days 4 years
Options, Outstanding, Intrinsic Value $ 36 $ 42
Options, Grants in Period, Gross 11,299  
Options, Grants in Period, Weighted Average Exercise Price $ 18.34  
Options, Exercises in Period 3,616,031  
Options, Exercises in Period, Weighted Average Exercise Price $ 13.72  
Options, Forfeitures in Period 0  
Options, Forfeitures in Period, Weighted Average Exercise Price $ 0.00  
Options, Expirations in Period 31,100  
Options, Expirations in Period, Weighted Average Exercise Price $ 17.70  
Options, Exercisable 12,270,330  
Options, Exercisable, Weighted Average Exercise Price $ 18.82  
Options, Exercisable, Weighted Average Remaining Contractual Term 2 years 8 months 13 days  
Options, Exercisable, Intrinsic Value 26  
Options, Vested and Expected to Vest, Outstanding 14,124,288  
Options, Vested and Expected to Vest, Outstanding, Weighted Average Exercise Price $ 18.24  
Options, Vested and Expected to Vest, Outstanding, Weighted Average Remaining Contractual Term 3 years 3 months 20 days  
Options, Vested and Expected to Vest, Outstanding, Aggregate Intrinsic Value $ 36