Quarterly report pursuant to Section 13 or 15(d)

Stock-Based Compensation (Schedule of Outstanding Awards) (Details)

v3.8.0.1
Stock-Based Compensation (Schedule of Outstanding Awards) (Details)
$ / shares in Units, shares in Thousands, $ in Millions
 3 Months Ended
Mar. 31, 2018
USD ($)
$ / shares
shares
Class A  
Awards  
Outstanding at beginning of period (in shares) | shares 1,670
Granted (in shares) | shares 0
Exercised (in shares) | shares (3)
Forfeited/Cancelled (in shares) | shares 0
Outstanding at end of period (in shares) | shares 1,667
Exercisable at end of period (in shares) | shares 1,306
WAEP  
Outstanding at beginning of period (in dollars per share) | $ / shares $ 47.12
Granted (in dollars per share) | $ / shares 0.00
Exercised (in dollars per share) | $ / shares 16.94
Forfeited/Cancelled (in dollars per share) | $ / shares 0.00
Outstanding at end of period (in dollars per share) | $ / shares 47.18
Exercisable at end of period (in dollars per share) | $ / shares $ 47.39
Weighted average remaining life  
Outstanding at end of period 2 years 4 months 24 days
Exercisable at end of period 1 year 9 months 18 days
Aggregate intrinsic value  
Outstanding at end of period | $ $ 13
Exercisable at end of period | $ $ 10
Class B  
Awards  
Outstanding at beginning of period (in shares) | shares 1,080
Granted (in shares) | shares 143
Exercised (in shares) | shares 0
Forfeited/Cancelled (in shares) | shares 0
Outstanding at end of period (in shares) | shares 1,223
Exercisable at end of period (in shares) | shares 443
WAEP  
Outstanding at beginning of period (in dollars per share) | $ / shares $ 56.38
Granted (in dollars per share) | $ / shares 54.01
Exercised (in dollars per share) | $ / shares 0.00
Forfeited/Cancelled (in dollars per share) | $ / shares 0.00
Outstanding at end of period (in dollars per share) | $ / shares 56.10
Exercisable at end of period (in dollars per share) | $ / shares $ 56.38
Weighted average remaining life  
Outstanding at end of period 4 years 9 months 18 days
Exercisable at end of period 5 years 6 months
Aggregate intrinsic value  
Outstanding at end of period | $ $ 0
Exercisable at end of period | $ $ 0