Earnings Per Common Share - Computation of EPS (Details) (USD $) In Millions, except Per Share data	3 Months Ended	6 Months Ended
Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Earnings Per Share Reconciliation [Abstract]
Net income	$ 13.5	$ 9.6	$ 31.4	$ 32.4
Preferred stock dividends	2.6	2.6	5.2	5.2
Net income applicable to common shareowners	10.9	7.0	26.2	27.2
Net income applicable to common shareowners, diluted	$ 10.9	$ 7.0	$ 26.2	$ 27.2
Weighted Average Number of Shares Outstanding Reconciliation [Abstract]
Weighted average common shares outstanding - basic	198.0	201.0	197.9	200.9
Warrants	0.2	1.6	0.1	1.3
Stock-based compensation arrangements	2.8	3.1	2.7	3.0
Weighted average common shares outstanding - diluted	201.0	205.7	200.7	205.2
Earnings per share, basic	$ 0.06	$ 0.03	$ 0.13	$ 0.14
Earnings per share, diluted	$ 0.05	$ 0.03	$ 0.13	$ 0.13

The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period.

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The amount of net income (loss) for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period.

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Additional shares included in the calculation of diluted EPS as a result of the potentially dilutive effect of call options and warrants using the treasury stock method.

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The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

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Net income after adjustments for dividends on preferred stock (declared in the period) and/or cumulative preferred stock (accumulated for the period).

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Net Income or Loss Available to Common Stockholders plus adjustments resulting from the assumption that dilutive convertible securities were converted, options or warrants were exercised, or that other shares were issued upon the satisfaction of certain conditions.

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The average number of shares or units issued and outstanding that are used in calculating diluted EPS or earnings per unit (EPU), determined based on the timing of issuance of shares or units in the period.

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