Earnings Per Common Share (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Numerator:
Net income (loss)	$ 0.8	$ 4.5	$ (35.9)	$ 17.1
Preferred stock dividends	2.6	2.6	5.2	5.2
(Loss) income available to common shareholders - basic and diluted	$ (1.8)	$ 1.9	$ (41.1)	$ 11.9
Denominator:
Weighted average common shares outstanding - basic	206.9	195.8	204.8	195.5
Warrants	0	3.1	0	3.1
Stock-based compensation arrangements	0	2.8	0	3.1
Weighted average common shares outstanding - diluted	206.9	201.7	204.8	201.7
Basic and diluted (loss) earnings per common share	$ (0.01)	$ 0.01	$ (0.20)	$ 0.06
Stock Compensation Plan [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount		7.2		7.1
Convertible Preferred Stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount		4.5		4.5