Quarterly report pursuant to Section 13 or 15(d)

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

v3.7.0.1
Share-Based Compensation - Summary of Activity Under Share-Based Compensation Plans (Detail) - USD ($)
$ / shares in Units, shares in Thousands, $ in Millions
3 Months Ended 6 Months Ended 12 Months Ended
Jun. 30, 2017
Jun. 30, 2016
Jun. 30, 2017
Jun. 30, 2016
Dec. 31, 2016
SARs [Member]          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Awards Outstanding, Beginning Balance     11,998    
Granted, Awards     1,350    
Exercised, Awards     (2,421)    
Forfeited, Awards     (247)    
Awards Outstanding, Ending Balance 10,680   10,680   11,998
Exercisable Awards, Ending Balance 6,337   6,337    
Weighted Average Exercise Price Outstanding, Beginning Balance     $ 41.52    
Granted, Weighted Average Exercise Price     57.25    
Exercised, Weighted Average Exercise Price     28.34    
Forfeited, Weighted Average Exercise Price     50.98    
Weighted Average Exercise Price Outstanding, Ending Balance $ 46.28   46.28   $ 41.52
Exercisable, Weighted Average Exercise Price, Ending Balance $ 45.56   $ 45.56    
Weighted Average Remaining Contractual Term Outstanding     6 years 6 months   6 years
Exercisable Weighted Average Remaining Contractual Term     5 years 1 month 6 days    
Aggregate Intrinsic Value Outstanding $ 275.1   $ 275.1   $ 148.7
Exercisable, Aggregate Intrinsic Value $ 170.9   $ 170.9    
Granted, Weighted Average Grant Date Fair Value $ 34.76 $ 29.77 $ 28.34 $ 29.47  
Incentive Plan and Independent Directors Stock Units [Member]          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Outstanding and nonvested December 31, 2016, Shares     26    
Granted, Shares     112    
Vested, Shares     (24)    
Outstanding and nonvested June 30, 2017, Shares 114   114   26
Outstanding and nonvested December 31, 2016, Weighted Average Grant Date Fair Value     $ 62.35    
Granted, Weighted Average Grant Date Fair Value     70.14    
Vested, Weighted Average Grant Date Fair Value     62.45    
Outstanding and nonvested June 30, 2017, Weighted Average Grant Date Fair Value $ 69.98   $ 69.98   $ 62.35