Quarterly report pursuant to Section 13 or 15(d)

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

v3.21.1
Share-Based Compensation - Summary of Activity Under Share-Based Compensation Plans (Detail) - USD ($)
$ / shares in Units, shares in Thousands, $ in Millions
3 Months Ended 12 Months Ended
Mar. 31, 2021
Mar. 31, 2020
Dec. 31, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Outstanding and nonvested, Beginning Balance, Number of Shares 3,068    
Granted, Number of Shares 1,460    
Vested, Number of Shares (764)    
Forfeited, Number of Shares (31)    
Outstanding and nonvested, Ending Balance, Number of Shares 3,733   3,068
Number of Shares, Expected to vest 3,263    
Outstanding and nonvested, Beginning Balance, Weighted Average Grant Date Fair Value Per Share $ 44.01    
Granted, Weighted Average Grant Date Fair Value Per Share 48.32    
Vested, Weighted Average Grant Date Fair Value Per Share 43.47    
Forfeited, Weighted Average Grant Date Fair Value Per Share 43.82    
Outstanding and nonvested, Ending Balance, Weighted Average Grant Date Fair Value Per Share 45.81   $ 44.01
Expected to vest, Ending Balance, Weighted Average Grant Date Fair Value Per Share $ 45.36    
SARs [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Number of Awards Outstanding, Beginning Balance 3,737    
Granted, Number of Awards 0 0  
Exercised, Number of Awards (560)    
Forfeited, Number of Awards 0    
Number of Awards Outstanding, Ending Balance 3,177   3,737
Number of Awards Exercisable, Ending Balance 3,177    
Number of Awards Vested and expected to vest, Ending Balance 3,177    
Weighted Average Exercise Price Per Award Outstanding, Beginning Balance $ 27.23    
Granted, Weighted Average Exercise Price Per Award 0    
Exercised, Weighted Average Exercise Price Per Award 29.65    
Forfeited, Weighted Average Exercise Price Per Award 0    
Weighted Average Exercise Price Per Award Outstanding, Ending Balance 26.81   $ 27.23
Exercisable, Weighted Average Exercise Price Per Award, Ending Balance 26.81    
Weighted Average Exercise Price Per Award, Vested and expected to vest, Ending Balance $ 26.81    
Weighted Average Remaining Contractual Term Outstanding 4 years 4 months 24 days   4 years 7 months 6 days
Exercisable Weighted Average Remaining Contractual Term 4 years 4 months 24 days    
Weighted Average Remaining Contractual Term, Vested and expected to vest 4 years 4 months 24 days    
Aggregate Intrinsic Value Outstanding $ 55.8   $ 77.8
Exercisable, Aggregate Intrinsic Value 55.8    
Aggregate Intrinsic Value, Vested and expected to vest $ 55.8