Outstanding Common Stock Equivalents That Were Anti-Dilutive (Detail) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010
Options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive shares	0.2	[1]	3.4	[1]	1.4	[1]
Warrants
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive shares	7.9	[2]	21.2	[2]	21.2	[2]
Shares Underlying 3 1/2% Convertible Senior Notes Due 2014
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive shares			21.2

[1] Represents all outstanding stock options for 2011. The weighted average exercise price for anti-dilutive options for 2012 and 2010 was $17.12 and $23.28, respectively.

[2] Represents all outstanding warrants for 2012, 2011 and 2010. The exercise price for the warrants is $22.50.