Quarterly report pursuant to Section 13 or 15(d)

Share-Based Compensation - Summary of Activity Under Share-Based Compensation Plans (Detail)

v3.5.0.2
Share-Based Compensation - Summary of Activity Under Share-Based Compensation Plans (Detail)
$ / shares in Units, shares in Thousands, $ in Millions
 9 Months Ended 12 Months Ended
Sep. 30, 2016
USD ($)
$ / shares
shares
Dec. 31, 2015
USD ($)
$ / shares
shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Awards Outstanding, Beginning Balance | shares 12,076  
Granted, Awards | shares 1,387  
Exercised, Awards | shares (1,076)  
Forfeited, Awards | shares (256)  
Awards Outstanding, Ending Balance | shares 12,131 12,076
Exercisable Awards, Ending Balance | shares 7,223  
Weighted Average Exercise Price Outstanding, Beginning Balance | $ / shares $ 38.70  
Granted, Weighted Average Exercise Price | $ / shares 62.27  
Exercised, Weighted Average Exercise Price | $ / shares 33.44  
Forfeited, Weighted Average Exercise Price | $ / shares 49.97  
Weighted Average Exercise Price Outstanding, Ending Balance | $ / shares 41.62 $ 38.70
Exercisable, Weighted Average Exercise Price, Ending Balance | $ / shares $ 39.00  
Weighted Average Remaining Contractual Term Outstanding 6 years 3 months 18 days 6 years 7 months 6 days
Exercisable Weighted Average Remaining Contractual Term 4 years 8 months 12 days  
Aggregate Intrinsic Value Outstanding, Beginning balance | $ $ 216.4  
Aggregate Intrinsic Value Outstanding, Ending balance | $ 265.3 $ 216.4
Exercisable, Aggregate Intrinsic Value, Ending Balance | $ $ 183.4  
Incentive Plan and Independent Directors Stock Units [Member]    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Outstanding and nonvested December 31, 2015, Shares | shares 34  
Granted, Shares | shares 27  
Vested, Shares | shares (34)  
Outstanding and nonvested September 30, 2016, Shares | shares 27 34
Outstanding and nonvested December 31, 2015, Weighted Average Grant Date Fair Value | $ / shares $ 51.08  
Granted, Weighted Average Grant Date Fair Value | $ / shares 62.51  
Vested, Weighted Average Grant Date Fair Value | $ / shares 51.25  
Outstanding and nonvested September 30, 2016, Weighted Average Grant Date Fair Value | $ / shares $ 62.51 $ 51.08