Fair Value Measurements and Credit Concentration (Nonrecurring Fair Value Measurements and Credit Concentration) (Details) (USD $)	Dec. 31, 2012	Dec. 31, 2012 Carrying Amount [Member]		Dec. 31, 2011 Carrying Amount [Member]		Dec. 31, 2012 Fair Value [Member]	Dec. 31, 2011 Fair Value [Member]	Dec. 31, 2012 Nonrecurring [Member] Carrying Amount [Member]		Sep. 30, 2011 Nonrecurring [Member] Carrying Amount [Member]		Jun. 30, 2011 Nonrecurring [Member] Carrying Amount [Member]		Mar. 31, 2011 Nonrecurring [Member] Carrying Amount [Member]		Dec. 31, 2010 Nonrecurring [Member] Carrying Amount [Member]		Sep. 30, 2010 Nonrecurring [Member] Carrying Amount [Member]		Jun. 30, 2010 Nonrecurring [Member] Carrying Amount [Member]		Mar. 31, 2010 Nonrecurring [Member] Carrying Amount [Member]		Dec. 31, 2012 Nonrecurring [Member] Level 2 [Member]	Sep. 30, 2011 Nonrecurring [Member] Level 2 [Member]	Jun. 30, 2011 Nonrecurring [Member] Level 2 [Member]		Mar. 31, 2011 Nonrecurring [Member] Level 2 [Member]	Dec. 31, 2010 Nonrecurring [Member] Level 2 [Member]	Sep. 30, 2010 Nonrecurring [Member] Level 2 [Member]	Jun. 30, 2010 Nonrecurring [Member] Level 2 [Member]	Mar. 31, 2010 Nonrecurring [Member] Level 2 [Member]	Dec. 31, 2012 Nonrecurring [Member] Level 3 [Member]	Sep. 30, 2011 Nonrecurring [Member] Level 3 [Member]	Jun. 30, 2011 Nonrecurring [Member] Level 3 [Member]	Mar. 31, 2011 Nonrecurring [Member] Level 3 [Member]	Dec. 31, 2010 Nonrecurring [Member] Level 3 [Member]		Sep. 30, 2010 Nonrecurring [Member] Level 3 [Member]		Jun. 30, 2010 Nonrecurring [Member] Level 3 [Member]		Mar. 31, 2010 Nonrecurring [Member] Level 3 [Member]		Dec. 31, 2012 Nonrecurring [Member] Loss [Member]		Sep. 30, 2011 Nonrecurring [Member] Loss [Member]		Jun. 30, 2011 Nonrecurring [Member] Loss [Member]		Mar. 31, 2011 Nonrecurring [Member] Loss [Member]		Dec. 31, 2010 Nonrecurring [Member] Loss [Member]		Sep. 30, 2010 Nonrecurring [Member] Loss [Member]		Jun. 30, 2010 Nonrecurring [Member] Loss [Member]		Mar. 31, 2010 Nonrecurring [Member] Loss [Member]		Dec. 31, 2012 PPL Energy Supply LLC [Member]	Dec. 31, 2012 PPL Energy Supply LLC [Member] Carrying Amount [Member]	Dec. 31, 2011 PPL Energy Supply LLC [Member] Carrying Amount [Member]	Dec. 31, 2012 PPL Energy Supply LLC [Member] Fair Value [Member]	Dec. 31, 2011 PPL Energy Supply LLC [Member] Fair Value [Member]	Sep. 30, 2011 PPL Energy Supply LLC [Member] Nonrecurring [Member] Carrying Amount [Member]		Jun. 30, 2011 PPL Energy Supply LLC [Member] Nonrecurring [Member] Carrying Amount [Member]		Mar. 31, 2011 PPL Energy Supply LLC [Member] Nonrecurring [Member] Carrying Amount [Member]		Dec. 31, 2010 PPL Energy Supply LLC [Member] Nonrecurring [Member] Carrying Amount [Member]		Sep. 30, 2010 PPL Energy Supply LLC [Member] Nonrecurring [Member] Carrying Amount [Member]		Jun. 30, 2010 PPL Energy Supply LLC [Member] Nonrecurring [Member] Carrying Amount [Member]		Mar. 31, 2010 PPL Energy Supply LLC [Member] Nonrecurring [Member] Carrying Amount [Member]		Sep. 30, 2011 PPL Energy Supply LLC [Member] Nonrecurring [Member] Level 2 [Member]	Jun. 30, 2011 PPL Energy Supply LLC [Member] Nonrecurring [Member] Level 2 [Member]		Mar. 31, 2011 PPL Energy Supply LLC [Member] Nonrecurring [Member] Level 2 [Member]	Dec. 31, 2010 PPL Energy Supply LLC [Member] Nonrecurring [Member] Level 2 [Member]	Sep. 30, 2010 PPL Energy Supply LLC [Member] Nonrecurring [Member] Level 2 [Member]	Jun. 30, 2010 PPL Energy Supply LLC [Member] Nonrecurring [Member] Level 2 [Member]	Mar. 31, 2010 PPL Energy Supply LLC [Member] Nonrecurring [Member] Level 2 [Member]	Sep. 30, 2011 PPL Energy Supply LLC [Member] Nonrecurring [Member] Level 3 [Member]	Jun. 30, 2011 PPL Energy Supply LLC [Member] Nonrecurring [Member] Level 3 [Member]	Mar. 31, 2011 PPL Energy Supply LLC [Member] Nonrecurring [Member] Level 3 [Member]	Dec. 31, 2010 PPL Energy Supply LLC [Member] Nonrecurring [Member] Level 3 [Member]		Sep. 30, 2010 PPL Energy Supply LLC [Member] Nonrecurring [Member] Level 3 [Member]		Jun. 30, 2010 PPL Energy Supply LLC [Member] Nonrecurring [Member] Level 3 [Member]		Mar. 31, 2010 PPL Energy Supply LLC [Member] Nonrecurring [Member] Level 3 [Member]		Sep. 30, 2011 PPL Energy Supply LLC [Member] Nonrecurring [Member] Loss [Member]		Jun. 30, 2011 PPL Energy Supply LLC [Member] Nonrecurring [Member] Loss [Member]		Mar. 31, 2011 PPL Energy Supply LLC [Member] Nonrecurring [Member] Loss [Member]		Dec. 31, 2010 PPL Energy Supply LLC [Member] Nonrecurring [Member] Loss [Member]		Sep. 30, 2010 PPL Energy Supply LLC [Member] Nonrecurring [Member] Loss [Member]		Jun. 30, 2010 PPL Energy Supply LLC [Member] Nonrecurring [Member] Loss [Member]		Mar. 31, 2010 PPL Energy Supply LLC [Member] Nonrecurring [Member] Loss [Member]		Dec. 31, 2012 PPL Electric Utilities Corp [Member] Carrying Amount [Member]	Dec. 31, 2011 PPL Electric Utilities Corp [Member] Carrying Amount [Member]	Dec. 31, 2012 PPL Electric Utilities Corp [Member] Fair Value [Member]	Dec. 31, 2011 PPL Electric Utilities Corp [Member] Fair Value [Member]	Dec. 31, 2012 LG And E And KU Energy LLC [Member] Carrying Amount [Member]	Dec. 31, 2011 LG And E And KU Energy LLC [Member] Carrying Amount [Member]	Dec. 31, 2012 LG And E And KU Energy LLC [Member] Fair Value [Member]	Dec. 31, 2011 LG And E And KU Energy LLC [Member] Fair Value [Member]	Dec. 31, 2012 LG And E And KU Energy LLC [Member] Nonrecurring [Member] Carrying Amount [Member]		Dec. 31, 2012 LG And E And KU Energy LLC [Member] Nonrecurring [Member] Level 2 [Member]	Dec. 31, 2012 LG And E And KU Energy LLC [Member] Nonrecurring [Member] Level 3 [Member]	Dec. 31, 2012 LG And E And KU Energy LLC [Member] Nonrecurring [Member] Loss [Member]		Dec. 31, 2012 Louisville Gas And Electric Co [Member] Carrying Amount [Member]	Dec. 31, 2011 Louisville Gas And Electric Co [Member] Carrying Amount [Member]	Dec. 31, 2012 Louisville Gas And Electric Co [Member] Fair Value [Member]	Dec. 31, 2011 Louisville Gas And Electric Co [Member] Fair Value [Member]	Dec. 31, 2012 Kentucky Utilities Co [Member] Carrying Amount [Member]	Dec. 31, 2011 Kentucky Utilities Co [Member] Carrying Amount [Member]	Dec. 31, 2012 Kentucky Utilities Co [Member] Fair Value [Member]	Dec. 31, 2011 Kentucky Utilities Co [Member] Fair Value [Member]	Dec. 31, 2012 Kentucky Utilities Co [Member] Nonrecurring [Member] Carrying Amount [Member]		Dec. 31, 2012 Kentucky Utilities Co [Member] Nonrecurring [Member] Level 2 [Member]	Dec. 31, 2012 Kentucky Utilities Co [Member] Nonrecurring [Member] Level 3 [Member]	Dec. 31, 2012 Kentucky Utilities Co [Member] Nonrecurring [Member] Loss [Member]
Nonrecurring Fair Value Measurements [Abstract]
Equity investment in EEI								$ 25,000,000	[1]																																				$ 25,000,000	[2]																																																																											$ 25,000,000	[1]			$ 25,000,000	[2]									$ 25,000,000	[1]			$ 25,000,000	[2]
Sulfur dioxide emission allowances																2,000,000	[1],[3]	6,000,000	[1],[3]	11,000,000	[1],[3]	13,000,000	[1],[3]														1,000,000	[3]	2,000,000	[3]	3,000,000	[3]	10,000,000	[3]									1,000,000	[2],[3]	4,000,000	[2],[3]	8,000,000	[2],[3]	3,000,000	[2],[3]												2,000,000	[1],[3]	6,000,000	[1],[3]	11,000,000	[1],[3]	13,000,000	[1],[3]												1,000,000	[3]	2,000,000	[3]	3,000,000	[3]	10,000,000	[3]							1,000,000	[2],[3]	4,000,000	[2],[3]	8,000,000	[2],[3]	3,000,000	[2],[3]
Certain non-core generation facilities																		473,000,000	[1]											381,000,000																									96,000,000	[2]																		473,000,000	[1]										381,000,000																						96,000,000	[2]
RECs										1,000,000	[1],[3]	2,000,000	[1],[3]	3,000,000	[1],[3]											1,000,000	[3]																				1,000,000	[2],[3]	1,000,000	[2],[3]	3,000,000	[2],[3]														1,000,000	[1],[3]	2,000,000	[1],[3]	3,000,000	[1],[3]										1,000,000	[3]																	1,000,000	[2],[3]	1,000,000	[2],[3]	3,000,000	[2],[3]
Fair value of Financial Instruments Not Recorded at Fair Value - Other
Contract adjustment payments		105,000,000	[4]	198,000,000	[4]	106,000,000	198,000,000
Long-term debt		19,476,000,000		17,993,000,000		21,671,000,000	19,392,000,000																																																							3,272,000,000	3,024,000,000	3,556,000,000	3,397,000,000																																																1,967,000,000	1,718,000,000	2,333,000,000	2,012,000,000	4,075,000,000	4,073,000,000	4,423,000,000	4,306,000,000							1,112,000,000	1,112,000,000	1,178,000,000	1,164,000,000	1,842,000,000	1,842,000,000	2,056,000,000	2,000,000,000
Credit Concentration Associated with Financial Instruments (Numeric) [Abstract]
Gross credit exposure from energy trading partners	1,800,000,000																																																												1,800,000,000
Net credit exposure to energy trading partners	688,000,000																																																												688,000,000
Dollar exposure to top ten energy trading counterparties	$ 367,000,000																																																												$ 367,000,000
Percentage exposure to top ten energy trading counterparties	53.00%																																																												53.00%

[1] Represents carrying value before fair value measurement.

[2] The loss on the EEI investment was recorded in the Kentucky Regulated segment and included in "Other-Than-Temporary Impairments" on the Statement of Income. Losses on sulfur dioxide emission allowances and RECs were recorded in the Supply segment and included in "Other operation and maintenance" on the Statements of Income. Losses on certain non-core generation facilities were recorded in the Supply segment and included in "Income (Loss) from Discontinued Operations (net of income taxes)" on the Statement of Income.

[3] Current and long-term sulfur dioxide emission allowances and RECs are included in "Other current assets" and "Other intangibles" in their respective areas on the Balance Sheets.

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