Commitments and Contingencies (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Future minimum payments for the next five years and thereafter for our operating lease contracts
2014	$ 3.9
2015	3.9
2016	3.7
2017	3.1
2018	3.2
Thereafter	22.7
Total	40.5
Manufactured Gas Plant Sites [Member]
Commitment and Contingencies (Textuals) [Abstract]
Reserves related to future remediation costs	36.9	38.2
Commitments and Contingencies (Textuals) [Abstract]
Estimated future detailed site investigation and remediation costs, minimum	19
Estimated Future detailed site investigation and remediation costs, maximum	56
Period for future costs of detailed site investigation and remediation costs	over the next ten years
Period to recover remediation cost of manufactured gas plant sites	5 years
Coal combustion product landfill sites [Member]
Commitment and Contingencies (Textuals) [Abstract]
Expense related to environmental remediation	0.1	0.3	0.2
Reserves related to landfill sites	0
Commitments and Contingencies (Textuals) [Abstract]
Expense related to environmental remediation	0.1	0.3	0.2
Minimum [Member]
Commitments and Contingencies [Line Items]
VAPP Conversion Cost	65
Maximum [Member]
Commitments and Contingencies [Line Items]
VAPP Conversion Cost	$ 70