Share-Based Compensation - Summary Of Stock Option Activity Under All Stock Plans (Detail) shares in Millions	12 Months Ended
	Dec. 31, 2016 $ / shares shares
Number Outstanding
Beginning balance (shares) | shares	4.2
Options granted (shares) | shares	0.3
Options exercised (shares) | shares	(1.3)
Options forfeited/expired (shares) | shares	(0.1)
Ending balance (shares) | shares	3.1
Weighted Average Exercise Price Per Share
Beginning balance (usd per share) | $ / shares	$ 421.00
Options granted (usd per share) | $ / shares	616.97
Options exercised (usd per share) | $ / shares	410.98
Options forfeited/expired (usd per share) | $ / shares	494.64
Ending balance (usd per share) | $ / shares	$ 445.09