Commitments and Contingencies (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended	12 Months Ended
	Mar. 31, 2014 Manufactured Gas Plant Sites [Member]	Dec. 31, 2013 Minimum [Member]	Dec. 31, 2013 Maximum [Member]
Commitments and Contingencies [Line Items]
Loss Contingency, Range of Possible Loss, Minimum	$ 19
Loss Contingency, Range of Possible Loss, Maximum	56
Period for future costs of detailed site investigation and remediation costs	over the next ten years
Accrual for Environmental Loss Contingencies, Provision for New Losses	36.9
VAPP Conversion Cost		$ 65	$ 70