Share Based Compensation - Schedule of Stock Option Activity (Detail) (USD $) In Millions, except Share data in Thousands, unless otherwise specified	9 Months Ended	12 Months Ended
	Sep. 30, 2014	Dec. 31, 2013
Shares Under Option
Outstanding at beginning of period	4,139
Exercised	(144)
Cancelled/forfeited/expired	(140)
Outstanding at end of period	3,855	4,139
Vested and expected to vest at end of period	3,828
Exercisable at end of period	1,363
Weighted Average Exercise Price Per Share
Outstanding at beginning of period	$ 19.39
Exercised	$ 10.90
Cancelled/forfeited/expired	$ 27.55
Outstanding at end of period	$ 19.42	$ 19.39
Vested and expected to vest at end of period	$ 19.46
Exercisable at end of period	$ 8.95
Weighted Average Remaining Contractual Term (years)
Outstanding	5 years	5 years 7 months 6 days
Vested and expected to vest at end of period	5 years
Exercisable at end of period	5 years 3 months 18 days
Aggregate Intrinsic Value
Outstanding at beginning of period	$ 21.2
Outstanding at end of period	11.9	21.2
Vested and expected to vest at end of period	11.9
Exercisable at end of period	$ 10.2