Commitments and Contingencies (Litigation) (Narrative) (Details) $ in Millions	1 Months Ended			3 Months Ended	12 Months Ended
	Aug. 31, 2014 USD ($)	Jun. 30, 2013 USD ($)	Oct. 31, 2012 USD ($) mi	Jun. 30, 2013 USD ($)	Dec. 31, 2014 USD ($)	Dec. 31, 2012 USD ($)	Dec. 31, 2011
Pending Litigation [Member] | PPL [Member]
Loss Contingencies [Line Items]
Contract price, pending litigation			$ 206.0
Construction contract, number of miles of transmission line | mi			100
Claims sought, pending litigation					$ 40.0
Pending Litigation [Member] | Sunlight Entities [Member]
Loss Contingencies [Line Items]
Claims sought, pending litigation		$ 60.0
Number of public solar projects							3
Number of arbitration proceedings					3
Arbitration award, pending litigation	$ 68.0
Pending Litigation [Member] | Sintel [Member]
Loss Contingencies [Line Items]
Legal settlement charges						$ 9.6
Resolved Litigation [Member] | Sintel [Member]
Loss Contingencies [Line Items]
Legal settlement charges				$ 2.8