Fair Value Measurements (Financial Instruments Not Recorded at Fair Value) (Details) - USD ($) $ in Millions	Sep. 30, 2015	Dec. 31, 2014
Carrying Amount [Member]
Fair Value of Financial Instruments Not Recorded at Fair Value - Other
Long-term debt	$ 19,205	$ 18,173
Fair Value [Member]
Fair Value of Financial Instruments Not Recorded at Fair Value - Other
Long-term debt	21,184	20,466
PPL Electric Utilities Corp [Member] | Carrying Amount [Member]
Fair Value of Financial Instruments Not Recorded at Fair Value - Other
Long-term debt	2,603	2,602
PPL Electric Utilities Corp [Member] | Fair Value [Member]
Fair Value of Financial Instruments Not Recorded at Fair Value - Other
Long-term debt	2,882	2,990
LG And E And KU Energy LLC [Member] | Carrying Amount [Member]
Fair Value of Financial Instruments Not Recorded at Fair Value - Other
Long-term debt	5,617	4,567
LG And E And KU Energy LLC [Member] | Fair Value [Member]
Fair Value of Financial Instruments Not Recorded at Fair Value - Other
Long-term debt	5,927	4,946
Louisville Gas And Electric Co [Member] | Carrying Amount [Member]
Fair Value of Financial Instruments Not Recorded at Fair Value - Other
Long-term debt	1,903	1,353
Louisville Gas And Electric Co [Member] | Fair Value [Member]
Fair Value of Financial Instruments Not Recorded at Fair Value - Other
Long-term debt	1,978	1,455
Kentucky Utilities Co [Member] | Carrying Amount [Member]
Fair Value of Financial Instruments Not Recorded at Fair Value - Other
Long-term debt	2,591	2,091
Kentucky Utilities Co [Member] | Fair Value [Member]
Fair Value of Financial Instruments Not Recorded at Fair Value - Other
Long-term debt	$ 2,763	$ 2,313