Equity Incentive Plans - Schedule of Stock Options Outstanding and Exercisable (Detail) - $ / shares	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options Outstanding, Number	20,015,180	21,372,960	22,640,942	25,007,776
Options Outstanding, Weighted Average Exercise Price	$ 46.13	$ 35.93
Options Outstanding, Weighted Average Remaining Contractual Life (in years)	4 years 6 months 18 days	5 years 5 months 23 days
Options Exercisable, Number	13,825,631	11,957,510
Options Exercisable, Weighted Average Exercise Price	$ 24.98	$ 12.37
Options Exercisable, Weighted Average Remaining Contractual Life (in years)	3 years 4 months 10 days	3 years 7 months 17 days
$2.70 - $6.15 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Price, Lower limit	$ 2.70	$ 2.70
Range of Exercise Price, Upper limit	$ 6.15	$ 6.15
Options Outstanding, Number	195,706	329,072
Options Outstanding, Weighted Average Exercise Price	$ 3.05	$ 3.13
Options Exercisable, Number	195,706	327,696
Options Exercisable, Weighted Average Exercise Price	$ 3.05	$ 3.13
$6.63 - $6.63 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Price, Lower limit	6.63	6.63
Range of Exercise Price, Upper limit	$ 6.63	$ 6.63
Options Outstanding, Number	6,915,441	7,030,489
Options Outstanding, Weighted Average Exercise Price	$ 6.63	$ 6.63
Options Exercisable, Number	6,915,142	7,029,293
Options Exercisable, Weighted Average Exercise Price	$ 6.63	$ 6.63
$9.96 - $30.06 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Price, Lower limit	9.96
Range of Exercise Price, Upper limit	$ 30.06
Options Outstanding, Number	2,049,342
Options Outstanding, Weighted Average Exercise Price	$ 25.13
Options Exercisable, Number	1,917,003
Options Exercisable, Weighted Average Exercise Price	$ 24.89
$30.08 - $31.07 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Price, Lower limit	30.08
Range of Exercise Price, Upper limit	$ 31.07
Options Outstanding, Number	294,030
Options Outstanding, Weighted Average Exercise Price	$ 30.77
Options Exercisable, Number	236,557
Options Exercisable, Weighted Average Exercise Price	$ 30.70
$31.17 - $31.17 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Price, Lower limit	31.17	31.17
Range of Exercise Price, Upper limit	$ 31.17	$ 31.17
Options Outstanding, Number	5,517,405	5,611,130
Options Outstanding, Weighted Average Exercise Price	$ 31.17	$ 31.17
Options Exercisable, Number	2,279,381	663,860
Options Exercisable, Weighted Average Exercise Price	$ 31.17	$ 31.17
$31.49 - $41.83 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Price, Lower limit	31.49
Range of Exercise Price, Upper limit	$ 41.83
Options Outstanding, Number	2,007,717
Options Outstanding, Weighted Average Exercise Price	$ 34.28
Options Exercisable, Number	1,531,818
Options Exercisable, Weighted Average Exercise Price	$ 33.60
$87.80 - $241.93 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Price, Lower limit	87.80
Range of Exercise Price, Upper limit	$ 241.93
Options Outstanding, Number	2,238,944
Options Outstanding, Weighted Average Exercise Price	$ 165.32
Options Exercisable, Number	648,292
Options Exercisable, Weighted Average Exercise Price	$ 146.31
$250.69 - $261.89 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Price, Lower limit	250.69
Range of Exercise Price, Upper limit	$ 261.89
Options Outstanding, Number	736,616
Options Outstanding, Weighted Average Exercise Price	$ 257.36
Options Exercisable, Number	96,232
Options Exercisable, Weighted Average Exercise Price	$ 259.50
$262.16 - $262.16 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Price, Lower limit	262.16
Range of Exercise Price, Upper limit	$ 262.16
Options Outstanding, Number	44,012
Options Outstanding, Weighted Average Exercise Price	$ 262.16
$282.11 - $282.11 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Price, Lower limit	282.11	282.11
Range of Exercise Price, Upper limit	$ 282.11	$ 282.11
Options Outstanding, Number	15,967	25,958
Options Outstanding, Weighted Average Exercise Price	$ 282.11	$ 282.11
Options Exercisable, Number	5,500
Options Exercisable, Weighted Average Exercise Price	$ 282.11
$9.96 - $28.45 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Price, Lower limit		9.96
Range of Exercise Price, Upper limit		$ 28.45
Options Outstanding, Number		2,183,386
Options Outstanding, Weighted Average Exercise Price		$ 23.87
Options Exercisable, Number		1,779,133
Options Exercisable, Weighted Average Exercise Price		$ 23.19
$29.12 - $31.07 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Price, Lower limit		29.12
Range of Exercise Price, Upper limit		$ 31.07
Options Outstanding, Number		1,105,021
Options Outstanding, Weighted Average Exercise Price		$ 30.00
Options Exercisable, Number		606,484
Options Exercisable, Weighted Average Exercise Price		$ 30.00
$31.49 - $38.42 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Price, Lower limit		31.49
Range of Exercise Price, Upper limit		$ 38.42
Options Outstanding, Number		2,376,417
Options Outstanding, Weighted Average Exercise Price		$ 33.25
Options Exercisable, Number		1,167,109
Options Exercisable, Weighted Average Exercise Price		$ 32.82
$39.10 - $179.72 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Price, Lower limit		39.10
Range of Exercise Price, Upper limit		$ 179.72
Options Outstanding, Number		2,140,496
Options Outstanding, Weighted Average Exercise Price		$ 111.51
Options Exercisable, Number		379,519
Options Exercisable, Weighted Average Exercise Price		$ 94.50
$184.67 - $259.32 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Price, Lower limit		184.67
Range of Exercise Price, Upper limit		$ 259.32
Options Outstanding, Number		498,658
Options Outstanding, Weighted Average Exercise Price		$ 233.06
Options Exercisable, Number		84
Options Exercisable, Weighted Average Exercise Price		$ 198.09
$259.94 - $259.94 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Price, Lower limit		259.94
Range of Exercise Price, Upper limit		$ 259.94
Options Outstanding, Number		72,333
Options Outstanding, Weighted Average Exercise Price		$ 259.94
Options Exercisable, Number		4,332
Options Exercisable, Weighted Average Exercise Price		$ 259.94