COMMON EQUITY (Details 2) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Numerator:
Net income (loss) from continuing operations	$ 97.8	$ 123.4
Discontinued operations, net of tax	1.9	0.1
Preferred stock dividends of subsidiary	(0.8)	(0.8)
Net income attributed to common shareholders	$ 98.9	$ 122.7
Denominator:
Average shares of common stock - basic	78.6	78.3
Effect of dilutive securities - Stock-based compensation (in shares)	0.4	0.3
Effect of dilutive securities - Deferred compensation (in shares)	0.2
Average shares of common stock - diluted	79.2	78.6
Earnings (Loss) per common share
Basic (in dollars per share)	$ 1.26	$ 1.57
Diluted (in dollars per share)	$ 1.25	$ 1.56
Out-of-the-money stock options
Disclosure of antidilutive shares
Antidilutive shares excluded from calculation of diluted earnings per share	0.8	0.8