Preferred and Common Stock - Schedule of Options Fully Vested Exercisable (Detail) (USD $) In Millions, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2013
Schedule Of Stock Options [Line Items]
Options Fully Vested and Exercisable, Number of options	30.4
Options Fully Vested and Exercisable, Weighted average remaining contractual life, years	3 years 3 months 22 days
Options Fully Vested and Exercisable, Weighted average exercise price	$ 11.16
Options Fully Vested and Exercisable, Intrinsic value	$ 39
$8.33 [Member]
Schedule Of Stock Options [Line Items]
Range of exercise price, lower unit	$ 8.33
Options Fully Vested and Exercisable, Number of options	16.3
Options Fully Vested and Exercisable, Weighted average remaining contractual life, years	1 year 22 days
Options Fully Vested and Exercisable, Weighted average exercise price	$ 8.33
Options Fully Vested and Exercisable, Intrinsic value	38
$8.34 - $11.33 [Member]
Schedule Of Stock Options [Line Items]
Range of exercise price, lower unit	$ 8.34
Range of exercise price, upper unit	$ 11.33
Options Fully Vested and Exercisable, Number of options	3.3
Options Fully Vested and Exercisable, Weighted average remaining contractual life, years	7 years 4 months 24 days
Options Fully Vested and Exercisable, Weighted average exercise price	$ 10.18
Options Fully Vested and Exercisable, Intrinsic value	$ 1
$11.34 - $17.40 [Member]
Schedule Of Stock Options [Line Items]
Range of exercise price, lower unit	$ 11.34
Range of exercise price, upper unit	$ 17.40
Options Fully Vested and Exercisable, Number of options	9.7
Options Fully Vested and Exercisable, Weighted average remaining contractual life, years	6 years 1 month 6 days
Options Fully Vested and Exercisable, Weighted average exercise price	$ 14.23
$17.41 - $34.84 [Member]
Schedule Of Stock Options [Line Items]
Range of exercise price, lower unit	$ 17.41
Range of exercise price, upper unit	$ 34.84
Options Fully Vested and Exercisable, Number of options	1.1
Options Fully Vested and Exercisable, Weighted average remaining contractual life, years	18 days
Options Fully Vested and Exercisable, Weighted average exercise price	$ 28.92