Earnings Per Common Share (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Numerator:
Net income (loss)	$ 9.3	$ 3.9	$ (26.6)	$ 21.0
Preferred stock dividends	2.6	2.6	7.8	7.8
Net income (loss) applicable to common shareholders - basic and diluted	$ 6.7	$ 1.3	$ (34.4)	$ 13.2
Denominator:
Weighted average common shares outstanding - basic	207.0	196.4	205.6	195.8
Warrants	0	5.6	0	3.9
Stock-based compensation arrangements	1.5	3.6	0	3.3
Weighted average common shares outstanding - diluted	208.5	205.6	205.6	203.0
Basic and diluted earnings (loss) per common share	$ 0.03	$ 0.01	$ (0.17)	$ 0.07
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	7.0	4.4		6.2
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	4.5	4.5