Share-Based Compensation Plans - Summary of Stock Option Activity (Detail) (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2014
Schedule Of Stock Option Activity [Line Items]
Options exercisable at December 31, 2013	0
Stock Options
Schedule Of Stock Option Activity [Line Items]
Number of shares, Outstanding, Beginning balance	3,051,939,000
Number of shares, Issued	130,978,000
Number of shares, Forfeited	(12,650,000)
Number of shares, Expired	(2,200,000)
Number of shares, Outstanding, Ending balance	3,168,067,000
Options exercisable at December 31, 2013	13,683,000
Weighted-average exercise price, Outstanding, Beginning balance	$ 12.42
Weighted-average exercise price, Issued	$ 17.78
Weighted-average exercise price, Forfeited	$ 17.72
Weighted-average exercise price, Expired	$ 27.95
Weighted-average exercise price, Outstanding, Ending balance	$ 12.61
Weighted-average exercise price, Exercisable	$ 16.67
Weighted-average remaining contractual term in years, Outstanding	7 years 2 months 12 days
Weighted-average remaining contractual term in years, Exercisable	2 years 6 months 11 days
Aggregate intrinsic value, Outstanding	$ 21,735
Aggregate intrinsic value, Exercisable	$ 65