Fair Value Measurements and Credit Concentration (Nonrecurring Fair Value Measurements and Credit Concentration) (Details) (USD $)	Sep. 30, 2013		Dec. 31, 2012
Credit Concentration Associated with Financial Instruments (Numeric) [Abstract]
Gross credit exposure from energy trading partners	$ 1,100,000,000
Net credit exposure to energy trading partners	541,000,000
Dollar exposure to top ten energy trading counterparties	292,000,000
Percentage exposure to top ten energy trading counterparties	54.00%
Number of counterparties in top ten that have investment grade credit rating	9
Percentage of top ten's exposure that consists of counterparties with investment grade credit rating (in hundreths)	95.00%
Carrying Amount [Member]
Fair Value of Financial Instruments Not Recorded at Fair Value - Other
Contract adjustment payments	32,000,000	[1]	105,000,000	[1]
Long-term debt	19,843,000,000		19,476,000,000
Fair Value [Member]
Fair Value of Financial Instruments Not Recorded at Fair Value - Other
Contract adjustment payments	32,000,000		106,000,000
Long-term debt	21,537,000,000		21,671,000,000
PPL Energy Supply LLC [Member]
Credit Concentration Associated with Financial Instruments (Numeric) [Abstract]
Gross credit exposure from energy trading partners	1,100,000,000
Net credit exposure to energy trading partners	540,000,000
Dollar exposure to top ten energy trading counterparties	292,000,000
Percentage exposure to top ten energy trading counterparties	54.00%
Number of counterparties in top ten that have investment grade credit rating	9
Percentage of top ten's exposure that consists of counterparties with investment grade credit rating (in hundreths)	95.00%
PPL Energy Supply LLC [Member] | Carrying Amount [Member]
Fair Value of Financial Instruments Not Recorded at Fair Value - Other
Long-term debt	2,962,000,000		3,272,000,000
PPL Energy Supply LLC [Member] | Fair Value [Member]
Fair Value of Financial Instruments Not Recorded at Fair Value - Other
Long-term debt	3,127,000,000		3,556,000,000
PPL Electric Utilities Corp [Member] | Carrying Amount [Member]
Fair Value of Financial Instruments Not Recorded at Fair Value - Other
Long-term debt	2,315,000,000		1,967,000,000
PPL Electric Utilities Corp [Member] | Fair Value [Member]
Fair Value of Financial Instruments Not Recorded at Fair Value - Other
Long-term debt	2,505,000,000		2,333,000,000
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	4,076,000,000		4,075,000,000
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	4,222,000,000		4,423,000,000
Louisville Gas And Electric Co [Member] | Carrying Amount [Member]
Fair Value of Financial Instruments Not Recorded at Fair Value - Other
Long-term debt	1,112,000,000		1,112,000,000
Louisville Gas And Electric Co [Member] | Fair Value [Member]
Fair Value of Financial Instruments Not Recorded at Fair Value - Other
Long-term debt	1,137,000,000		1,178,000,000
Kentucky Utilities Co [Member] | Carrying Amount [Member]
Fair Value of Financial Instruments Not Recorded at Fair Value - Other
Long-term debt	1,843,000,000		1,842,000,000
Kentucky Utilities Co [Member] | Fair Value [Member]
Fair Value of Financial Instruments Not Recorded at Fair Value - Other
Long-term debt	$ 1,940,000,000		$ 2,056,000,000

[1] Reflected in "Other current liabilities" and "Other deferred credits and noncurrent liabilities" on the Balance Sheets.