Other Commitments And Contingencies (Existence And Expiration Of Commercial Commitments) (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2012
Other Commitments And Contingencies [Line Items]
2012	$ 567.0
2013	694.5
2014	533.2
2015	579.2
2016	291.6
After	5,190.7
Total	7,856.2
Guarantees Of Subsidiaries Debt [Member]
Other Commitments And Contingencies [Line Items]
2012	315.0
2013	420.3
2014	500.0
2015	480.0
2016	291.6
After	5,114.0
Total	7,120.9
Guarantees Supporting Energy Commodity Transactions Of Subsidiaries [Member]
Other Commitments And Contingencies [Line Items]
2012	3.3
2013	25.2
2014	0
2015	80.0
2016	0
After	0.7
Total	109.2
Accounts Receivable Securitization [Member]
Other Commitments And Contingencies [Line Items]
2012	170.3
2013	0
2014	0
2015	0
2016	0
After	0
Total	170.3
Lines Of Credit [Member]
Other Commitments And Contingencies [Line Items]
2012	55.0
2013	0
2014	0
2015	0
2016	0
After	0
Total	55.0
Letters Of Credit [Member]
Other Commitments And Contingencies [Line Items]
2012	0.4
2013	19.3
2014	1.0
2015	16.2
2016	0
After	0
Total	36.9
Other Guarantees [Member]
Other Commitments And Contingencies [Line Items]
2012	23.0
2013	229.7
2014	32.2
2015	3.0
2016	0
After	76.0
Total	$ 363.9