Discontinued Operations And Assets And Liabilities Held For Sale (Summary Of Gain (Loss) On Disposition Of Discontinued Operations Net Of Taxes) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net Revenues from Discontinued Operations									$ 0	$ 2.5	$ 37.1
(Loss) Income from discontinued operations									(1.0)	11.6	11.3
Income tax (benefit) expense									(0.3)	5.3	4.0
(Loss) Income from Discontinued Operations - net of taxes	(0.1)	(0.1)	(0.3)	(0.2)	(1.2)	(1.4)	(0.7)	44.5	(0.7)	6.3	7.3
Gain on Disposition of Discontinued Operations - net of taxes									0	34.9	0
Unregulated Natural Gas Marketing Business [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain on Disposition of Discontinued Operations - net of taxes										(1.5)
Service Plan And Leasing Business Lines of Retail Services Business [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain on Disposition of Discontinued Operations - net of taxes										$ 36.4