Stock-Based Compensation and Other Stock Plans - Summary of Stock Option Activity and Stock-settled SARs (Detail) $ / shares in Units, shares in Thousands, $ in Millions	3 Months Ended
	Mar. 31, 2018 USD ($) $ / shares shares
Stock Option
Shares (in thousands)
Beginning balance (in shares) | shares	3,198
Granted (in shares) | shares	515
Exercised (in shares) | shares	(137)
Forfeited or expired (in shares) | shares	(10)
Ending balance (in shares) | shares	3,566
Exercisable at March 31, 2018 (in shares) | shares	2,446
Exercise Price Per Share
Beginning balance (in dollars per share) | $ / shares	$ 115.30
Granted (in dollars per share) | $ / shares	161.18
Exercised (in dollars per share) | $ / shares	83.75
Forfeited or expired (in dollars per share) | $ / shares	157.97
Ending balance (in dollars per share) | $ / shares	123.02
Exercisable at March 31, 2018 (in dollars per share) | $ / shares	$ 106.15
Additional Disclosures
Outstanding, remaining contractual term (in years)	6 years 8 months 5 days
Exercisable, remaining contractual term (in years)	5 years 7 months 2 days
Outstanding, aggregate intrinsic value | $	$ 107.5
Exercisable, aggregate intrinsic value | $	$ 105.6
Stock-Settled SARs
Stock-settled SARs (in thousands)
Ending balance (in shares) | shares	424
Granted (in shares) | shares	89
Exercised (in shares) | shares	(8)
Forfeited or expired (in shares) | shares	(17)
Beginning balance (in shares) | shares	360
Exercisable at March 31, 2018 (in shares) | shares	240
Exercise Price Per Share
Beginning balance (in dollars per share) | $ / shares	$ 138.63
Granted (in dollars per share) | $ / shares	161.18
Exercised (in dollars per share) | $ / shares	101.87
Forfeited or expired (in dollars per share) | $ / shares	126.80
Ending balance (in dollars per share) | $ / shares	144.50
Exercisable at March 31, 2018 (in dollars per share) | $ / shares	$ 132.62
Additional Disclosures
Outstanding, remaining contractual term	7 years 10 months 10 days
Exercisable, remaining contractual term	7 years
Outstanding, aggregate intrinsic value | $	$ 4.6
Exercisable, aggregate intrinsic value | $	$ 4.3