Share-Based Compensation - Activity Related to Stock Options (Detail) - Stock Option Awards - $ / shares	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Number of shares
Balance at beginning of the period (in shares)	721,538,000	813,777,000
Granted (in shares)	78,434,000	152,209,000
Exercised (in shares)	(74,236,000)	(72,258,000)
Forfeited or expired (in shares)	(26,675,000)	(49,636,000)
Balance at end of the period (in shares)	699,061,000	844,092,000
Exercisable at period end (in shares)	463,326,000	538,751,000
Weighted Average Exercise Price
Balance at beginning of the period (in usd per share)	$ 55.38	$ 56.99
Granted (in usd per share)	85.03	47.63
Exercised (in usd per share)	55.77	55.28
Forfeited or expired (in usd per share)	68.93	60.06
Balance at end of the period (in usd per share)	58.15	55.27
Exercisable at period end (in usd per share)	$ 55.68	$ 56.40