Fair Value Measurements and Credit Concentration (Financial Instruments Not Recorded at Fair Value and Credit Concentration) (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Credit Concentration Associated with Financial Instruments (Numeric) [Abstract]
Gross credit exposure from energy trading partners	$ 649
Net credit exposure to energy trading partners	319
Dollar exposure to top ten energy trading counterparties	190
Percentage exposure to top ten energy trading counterparties	59.00%
Number of counterparties in top ten that have investment grade credit rating	8
Percentage of top ten's exposure that consists of counterparties with investment grade credit rating (in hundreths)	87.00%
Carrying Amount [Member]
Fair Value of Financial Instruments Not Recorded at Fair Value - Other
Contract adjustment payments		21	[1]
Long-term debt	20,757	20,907
Fair Value [Member]
Fair Value of Financial Instruments Not Recorded at Fair Value - Other
Contract adjustment payments		22
Long-term debt	22,854	22,177
PPL Energy Supply LLC [Member]
Credit Concentration Associated with Financial Instruments (Numeric) [Abstract]
Gross credit exposure from energy trading partners	649
Net credit exposure to energy trading partners	319
Dollar exposure to top ten energy trading counterparties	190
Percentage exposure to top ten energy trading counterparties	59.00%
Number of counterparties in top ten that have investment grade credit rating	8
Percentage of top ten's exposure that consists of counterparties with investment grade credit rating (in hundreths)	87.00%
PPL Energy Supply LLC [Member] | Carrying Amount [Member]
Fair Value of Financial Instruments Not Recorded at Fair Value - Other
Long-term debt	2,218	2,525
PPL Energy Supply LLC [Member] | Fair Value [Member]
Fair Value of Financial Instruments Not Recorded at Fair Value - Other
Long-term debt	2,267	2,658
PPL Electric Utilities Corp [Member] | Carrying Amount [Member]
Fair Value of Financial Instruments Not Recorded at Fair Value - Other
Long-term debt	2,602	2,315
PPL Electric Utilities Corp [Member] | Fair Value [Member]
Fair Value of Financial Instruments Not Recorded at Fair Value - Other
Long-term debt	2,919	2,483
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	4,566	4,565
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	4,920	4,672
Louisville Gas And Electric Co [Member] | Carrying Amount [Member]
Fair Value of Financial Instruments Not Recorded at Fair Value - Other
Long-term debt	1,353	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	1,443	1,372
Kentucky Utilities Co [Member] | Carrying Amount [Member]
Fair Value of Financial Instruments Not Recorded at Fair Value - Other
Long-term debt	2,091	2,091
Kentucky Utilities Co [Member] | Fair Value [Member]
Fair Value of Financial Instruments Not Recorded at Fair Value - Other
Long-term debt	$ 2,287	$ 2,155

[1] Included in "Other current liabilities" on the Balance Sheets.