Variable Interest Entities (Details) (Lower Mount Bethel Energy, LLC [Member], USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Variable Interest Entities [Line Items]
Original acquisition cost of the facility owned by a VIE	$ 455
Residual value guarantee percentage associated with VIE lease	70.52%
Debt associated with a VIE		437
Non-controlling interests associated with VIE		18
Additional depreciation expense for leasehold improvements associated with VIE	12	16	16
Amount paid during the period to purchase the Lower Mount Bethel plant, a consolidated Variable Interest Entity	455
Portion of purchase price paid to retire associated debt of the consolidated Variable Interest Entity	437
Portion of purchase price paid to make distribution to non controlling interest associated with the consolidated Variable Interest Entity	18
PPL Energy Supply LLC [Member]
Variable Interest Entities [Line Items]
Original acquisition cost of the facility owned by a VIE	455
Residual value guarantee percentage associated with VIE lease	70.52%
Debt associated with a VIE		437
Non-controlling interests associated with VIE		18
Additional depreciation expense for leasehold improvements associated with VIE	12	16	16
Amount paid during the period to purchase the Lower Mount Bethel plant, a consolidated Variable Interest Entity	455
Portion of purchase price paid to retire associated debt of the consolidated Variable Interest Entity	437
Portion of purchase price paid to make distribution to non controlling interest associated with the consolidated Variable Interest Entity	$ 18