Financing Activities (Short-term Debt) (Details) (Commercial Paper [Member], USD $) In Millions, unless otherwise specified	3 Months Ended	12 Months Ended	3 Months Ended		12 Months Ended		3 Months Ended	12 Months Ended		3 Months Ended	12 Months Ended	3 Months Ended		12 Months Ended		3 Months Ended	12 Months Ended		3 Months Ended	12 Months Ended		3 Months Ended	12 Months Ended
	Mar. 31, 2013 PPL Energy Supply [Member]	Dec. 31, 2012 PPL Energy Supply [Member]	Mar. 31, 2013 PPL Electric [Member]	Mar. 31, 2013 LGE [Member]	Dec. 31, 2012 LGE [Member]	Apr. 30, 2013 LGE [Member] Short Term Debt Activity Subsequent To Period End [Member]	Mar. 31, 2013 KU [Member]	Dec. 31, 2012 KU [Member]	Apr. 30, 2013 KU [Member] Short Term Debt Activity Subsequent To Period End [Member]	Mar. 31, 2013 PPL Energy Supply LLC [Member]	Dec. 31, 2012 PPL Energy Supply LLC [Member]	Mar. 31, 2013 PPL Electric Utilities Corp [Member]	Mar. 31, 2013 LG And E And KU Energy LLC [Member] LGE [Member]	Dec. 31, 2012 LG And E And KU Energy LLC [Member] LGE [Member]	Apr. 30, 2013 LG And E And KU Energy LLC [Member] LGE [Member] Short Term Debt Activity Subsequent To Period End [Member]	Mar. 31, 2013 LG And E And KU Energy LLC [Member] KU [Member]	Dec. 31, 2012 LG And E And KU Energy LLC [Member] KU [Member]	Apr. 30, 2013 LG And E And KU Energy LLC [Member] KU [Member] Short Term Debt Activity Subsequent To Period End [Member]	Mar. 31, 2013 Louisville Gas And Electric Co [Member]	Dec. 31, 2012 Louisville Gas And Electric Co [Member]	Apr. 30, 2013 Louisville Gas And Electric Co [Member] Short Term Debt Activity Subsequent To Period End [Member]	Mar. 31, 2013 Kentucky Utilities Co [Member]	Dec. 31, 2012 Kentucky Utilities Co [Member]	Apr. 30, 2013 Kentucky Utilities Co [Member] Short Term Debt Activity Subsequent To Period End [Member]
Short-term Debt [Line Items]
Capacity	$ 750		$ 300	$ 250		$ 350	$ 250		$ 350	$ 750		$ 300	$ 250		$ 350	$ 250		$ 350	$ 250		$ 350	$ 250		$ 350
Commercial paper outstanding	$ 481	$ 356	$ 125	$ 70	$ 55		$ 115	$ 70		$ 481	$ 356	$ 125	$ 70	$ 55		$ 115	$ 70		$ 70	$ 55		$ 115	$ 70
Weighted-average interest rate on outstanding commercial paper	0.38%	0.50%	0.39%	0.36%	0.42%		0.36%	0.42%		0.38%	0.50%	0.39%	0.36%	0.42%		0.36%	0.42%		0.36%	0.42%		0.36%	0.42%