CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Parenthetical) (USD $) In Millions, unless otherwise specified	12 Months Ended						2 Months Ended	12 Months Ended		10 Months Ended	2 Months Ended	12 Months Ended		10 Months Ended	2 Months Ended	12 Months Ended		10 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2012 PPL Energy Supply LLC [Member]	Dec. 31, 2011 PPL Energy Supply LLC [Member]	Dec. 31, 2010 PPL Energy Supply LLC [Member]	Dec. 31, 2010 LG And E And KU Energy LLC [Member] Successor [Member]	Dec. 31, 2012 LG And E And KU Energy LLC [Member] Successor [Member]	Dec. 31, 2011 LG And E And KU Energy LLC [Member] Successor [Member]	Oct. 31, 2010 LG And E And KU Energy LLC [Member] Predecessor [Member]	Dec. 31, 2010 Louisville Gas And Electric Co [Member] Successor [Member]	Dec. 31, 2012 Louisville Gas And Electric Co [Member] Successor [Member]	Dec. 31, 2011 Louisville Gas And Electric Co [Member] Successor [Member]	Oct. 31, 2010 Louisville Gas And Electric Co [Member] Predecessor [Member]	Dec. 31, 2010 Kentucky Utilities Co [Member] Successor [Member]	Dec. 31, 2012 Kentucky Utilities Co [Member] Successor [Member]	Dec. 31, 2011 Kentucky Utilities Co [Member] Successor [Member]	Oct. 31, 2010 Kentucky Utilities Co [Member] Predecessor [Member]
Tax effect of foreign currency translation adjustments arising during the period	$ 2	$ (2)	$ (1)	$ 0	$ 0	$ (1)
Tax effect of available-for-sale securities arising during the period	(31)	(6)	(31)	(31)	(6)	(31)
Tax effect of qualifying derivatives arising during the period	(32)	(139)	(148)	(46)	(164)	(207)	0	0	0	(7)	0	0	0	(7)
Tax effect of equity investees' other comprehensive income (loss) arising during the period	(1)	0	0				0	(1)	0	1
Tax effect of defined benefit plans - prior service costs arising during period	0	(1)	(14)	0	(2)	(8)	0	0	1	0
Tax effect of defined benefit plans - net actuarial gain (loss) arising during period	343	58	50	56	13	36	(3)	13	(1)	15
Tax effect of defined benefit plans - net transition obligation arising during period	0	0	(4)	0	0	(3)
Tax effect of available-for-sale securities reclassified to net income	1	5	3	1	5	3
Tax effect of qualifying derivatives reclassified to net income	278	246	84	291	242	99
Tax effect of equity investees' other comprehensive (income) loss reclassified to net income	0	0	0	0	0	0									0	(1)	0	1
Tax effect of prior service costs reclassified to net income	(5)	(5)	(7)	(2)	(3)	(5)	0	0	0	(1)
Tax effect of net actuarial loss reclassified to net income	(29)	(19)	(14)	(2)	(2)	(14)	0	0	1	(1)
Tax effect of transition obligation reclassified to net income	$ 0	$ 0	$ (1)	$ 0	$ 0	$ (1)