v2.4.0.8
Share-Based Compensation (Summary of Share-Based Compensation Expense) (Details) (USD $)
In Millions, unless otherwise specified
3 Months Ended 9 Months Ended
Sep. 30, 2013
Sep. 30, 2012
Sep. 30, 2013
Sep. 30, 2012
Share-Based Compensation [Abstract]        
Share-based compensation expense before income taxes $ 14 $ 12 $ 32 $ 34
Income tax benefit (6) (5) (13) (14)
Share-based compensation expense after income taxes $ 8 $ 7 $ 19 $ 20