Fair Value Measurements - Financial Instruments Not Recorded at Fair Value (Details) - USD ($) $ in Millions		Sep. 30, 2016	Dec. 31, 2015
Carrying Amount [Member]
Fair Value of Financial Instruments Not Recorded at Fair Value - Other
Long-term debt	[1]	$ 18,512	$ 19,048
Fair Value [Member]
Fair Value of Financial Instruments Not Recorded at Fair Value - Other
Long-term debt		23,180	21,218
PPL Electric Utilities Corp [Member] | Carrying Amount [Member]
Fair Value of Financial Instruments Not Recorded at Fair Value - Other
Long-term debt	[1]	2,831	2,828
PPL Electric Utilities Corp [Member] | Fair Value [Member]
Fair Value of Financial Instruments Not Recorded at Fair Value - Other
Long-term debt		3,372	3,088
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	[1]	5,089	5,088
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		5,832	5,384
Louisville Gas And Electric Co [Member] | Carrying Amount [Member]
Fair Value of Financial Instruments Not Recorded at Fair Value - Other
Long-term debt	[1]	1,642	1,642
Louisville Gas And Electric Co [Member] | Fair Value [Member]
Fair Value of Financial Instruments Not Recorded at Fair Value - Other
Long-term debt		1,852	1,704
Kentucky Utilities Co [Member] | Carrying Amount [Member]
Fair Value of Financial Instruments Not Recorded at Fair Value - Other
Long-term debt	[1]	2,327	2,326
Kentucky Utilities Co [Member] | Fair Value [Member]
Fair Value of Financial Instruments Not Recorded at Fair Value - Other
Long-term debt		$ 2,701	$ 2,467

[1] Amounts are net of debt issuance costs.