Stock-Based Compensation - Activity, Pricing and Other Information for Stock Options (Detail) (USD $)	12 Months Ended
	Dec. 31, 2014
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Number of Options Outstanding, Beginning Balance	25,705,942
Granted, Number of Options	730,611
Exercised, Number of Options	(3,050,309)
Lapsed or canceled, Number of Options	(3,470,688)
Number of Options Outstanding, Ending Balance	19,915,556
Expected to vest, Number of Options	3,045,216
Number of Options Exercisable, Ending Balance	16,635,502
Weighted-Average Exercise Price Per Option Outstanding, Beginning Balance	$ 19.83
Granted, Weighted-Average Exercise Price Per Option	$ 12.92
Exercised, Weighted-Average Exercise Price Per Option	$ 8.72
Lapsed or canceled, Weighted-Average Exercise Price Per Option	$ 29.09
Weighted-Average Exercise Price Per Option Outstanding, Ending Balance	$ 19.67
Expected to vest, Weighted-Average Exercise Price Per Option	$ 9.37
Weighted-Average Exercise Price Per Option Exercisable, Beginning Balance	$ 21.69
Weighted-Average Remaining Life (Years) Outstanding, Ending Balance	3 years 9 months 18 days
Expected to vest, Weighted-Average Remaining Life (Years)	7 years 7 months 6 days
Weighted-Average Remaining Life (Years) Exercisable, Ending Balance	3 years 0 days
Aggregate Intrinsic Value Outstanding, Ending Balance	$ 58
Expected to vest, Aggregate Intrinsic Value	14
Aggregate Intrinsic Value Exercisable, Ending Balance	$ 44