Fair Value Measurements and Credit Concentration (Assets and Liabilities Measured on Recurring Basis Table) (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2014		Dec. 31, 2013
Price risk management liabilities:
Total price risk management liabilities	$ 1,274		$ 1,244
Recurring [Member]
Assets
Cash and cash equivalents	1,188		1,102
Restricted cash and cash equivalents	324	[1]	134	[1]
Price risk management assets:
Energy commodities assets	1,041		1,188
Interest rate swaps assets	6		91
Foreign currency contracts assets	51		0
Total price risk management assets	1,098		1,279
NDT funds	911		864
Auction rate securities	13	[2]	19	[2]
Total assets	3,534		3,398
Price risk management liabilities:
Energy commodities liabilities	1,137		1,070
Interest rate swaps liabilities	64		36
Foreign currency contracts liabilities	26		106
Cross-currency swaps liabilities	47		32
Total price risk management liabilities	1,274		1,244
Recurring [Member] | Cash And Cash Equivalents [Member]
Price risk management assets:
NDT funds	17		14
Recurring [Member] | United States Large Cap Equity Securities [Member]
Price risk management assets:
NDT funds	582		547
Recurring [Member] | United States Mid Small Cap Equity Securities [Member]
Price risk management assets:
NDT funds	83		81
Recurring [Member] | United States Treasury Debt Securities [Member]
Price risk management assets:
NDT funds	98		95
Recurring [Member] | United States Government Sponsored Agency Debt Securities [Member]
Price risk management assets:
NDT funds	6		6
Recurring [Member] | Municipality Debt Securities [Member]
Price risk management assets:
NDT funds	77		77
Recurring [Member] | Investment Grade Corporate Debt Securities [Member]
Price risk management assets:
NDT funds	40		38
Recurring [Member] | Other Debt Securities [Member]
Price risk management assets:
NDT funds	6		5
Recurring [Member] | Receivables Payables Net [Member]
Price risk management assets:
NDT funds	2		1
Recurring [Member] | Level 1 [Member]
Assets
Cash and cash equivalents	1,188		1,102
Restricted cash and cash equivalents	324	[1]	134	[1]
Price risk management assets:
Energy commodities assets	4		3
Interest rate swaps assets	0		0
Foreign currency contracts assets	0		0
Total price risk management assets	4		3
NDT funds	582		550
Auction rate securities	0		0
Total assets	2,098		1,789
Price risk management liabilities:
Energy commodities liabilities	2		4
Interest rate swaps liabilities	0		0
Foreign currency contracts liabilities	0		0
Cross-currency swaps liabilities	0		0
Total price risk management liabilities	2		4
Recurring [Member] | Level 1 [Member] | Cash And Cash Equivalents [Member]
Price risk management assets:
NDT funds	17		14
Recurring [Member] | Level 1 [Member] | United States Large Cap Equity Securities [Member]
Price risk management assets:
NDT funds	432		409
Recurring [Member] | Level 1 [Member] | United States Mid Small Cap Equity Securities [Member]
Price risk management assets:
NDT funds	35		33
Recurring [Member] | Level 1 [Member] | United States Treasury Debt Securities [Member]
Price risk management assets:
NDT funds	98		95
Recurring [Member] | Level 1 [Member] | United States Government Sponsored Agency Debt Securities [Member]
Price risk management assets:
NDT funds	0		0
Recurring [Member] | Level 1 [Member] | Municipality Debt Securities [Member]
Price risk management assets:
NDT funds	0		0
Recurring [Member] | Level 1 [Member] | Investment Grade Corporate Debt Securities [Member]
Price risk management assets:
NDT funds	0		0
Recurring [Member] | Level 1 [Member] | Other Debt Securities [Member]
Price risk management assets:
NDT funds	0		0
Recurring [Member] | Level 1 [Member] | Receivables Payables Net [Member]
Price risk management assets:
NDT funds	0		(1)
Recurring [Member] | Level 2 [Member]
Assets
Cash and cash equivalents	0		0
Restricted cash and cash equivalents	0		0
Price risk management assets:
Energy commodities assets	945		1,123
Interest rate swaps assets	6		91
Foreign currency contracts assets	51		0
Total price risk management assets	1,002		1,214
NDT funds	329		314
Auction rate securities	0		0
Total assets	1,331		1,528
Price risk management liabilities:
Energy commodities liabilities	1,063		1,028
Interest rate swaps liabilities	64		36
Foreign currency contracts liabilities	26		106
Cross-currency swaps liabilities	47		32
Total price risk management liabilities	1,200		1,202
Recurring [Member] | Level 2 [Member] | Cash And Cash Equivalents [Member]
Price risk management assets:
NDT funds	0		0
Recurring [Member] | Level 2 [Member] | United States Large Cap Equity Securities [Member]
Price risk management assets:
NDT funds	150		138
Recurring [Member] | Level 2 [Member] | United States Mid Small Cap Equity Securities [Member]
Price risk management assets:
NDT funds	48		48
Recurring [Member] | Level 2 [Member] | United States Treasury Debt Securities [Member]
Price risk management assets:
NDT funds	0		0
Recurring [Member] | Level 2 [Member] | United States Government Sponsored Agency Debt Securities [Member]
Price risk management assets:
NDT funds	6		6
Recurring [Member] | Level 2 [Member] | Municipality Debt Securities [Member]
Price risk management assets:
NDT funds	77		77
Recurring [Member] | Level 2 [Member] | Investment Grade Corporate Debt Securities [Member]
Price risk management assets:
NDT funds	40		38
Recurring [Member] | Level 2 [Member] | Other Debt Securities [Member]
Price risk management assets:
NDT funds	6		5
Recurring [Member] | Level 2 [Member] | Receivables Payables Net [Member]
Price risk management assets:
NDT funds	2		2
Recurring [Member] | Level 3 [Member]
Assets
Cash and cash equivalents	0		0
Restricted cash and cash equivalents	0		0
Price risk management assets:
Energy commodities assets	92		62
Interest rate swaps assets	0		0
Foreign currency contracts assets	0		0
Total price risk management assets	92		62
NDT funds	0		0
Auction rate securities	13	[2]	19	[2]
Total assets	105		81
Price risk management liabilities:
Energy commodities liabilities	72		38
Interest rate swaps liabilities	0		0
Foreign currency contracts liabilities	0		0
Cross-currency swaps liabilities	0		0
Total price risk management liabilities	72		38
Recurring [Member] | Level 3 [Member] | Cash And Cash Equivalents [Member]
Price risk management assets:
NDT funds	0		0
Recurring [Member] | Level 3 [Member] | United States Large Cap Equity Securities [Member]
Price risk management assets:
NDT funds	0		0
Recurring [Member] | Level 3 [Member] | United States Mid Small Cap Equity Securities [Member]
Price risk management assets:
NDT funds	0		0
Recurring [Member] | Level 3 [Member] | United States Treasury Debt Securities [Member]
Price risk management assets:
NDT funds	0		0
Recurring [Member] | Level 3 [Member] | United States Government Sponsored Agency Debt Securities [Member]
Price risk management assets:
NDT funds	0		0
Recurring [Member] | Level 3 [Member] | Municipality Debt Securities [Member]
Price risk management assets:
NDT funds	0		0
Recurring [Member] | Level 3 [Member] | Investment Grade Corporate Debt Securities [Member]
Price risk management assets:
NDT funds	0		0
Recurring [Member] | Level 3 [Member] | Other Debt Securities [Member]
Price risk management assets:
NDT funds	0		0
Recurring [Member] | Level 3 [Member] | Receivables Payables Net [Member]
Price risk management assets:
NDT funds	0		0
PPL Energy Supply LLC [Member] | Recurring [Member]
Assets
Cash and cash equivalents	194		239
Restricted cash and cash equivalents	284	[1]	85	[1]
Price risk management assets:
Energy commodities assets	1,041		1,188
Total price risk management assets	1,041		1,188
NDT funds	911		864
Auction rate securities	10	[2]	16	[2]
Total assets	2,440		2,392
Price risk management liabilities:
Energy commodities liabilities	1,137		1,070
Total price risk management liabilities	1,137		1,070
PPL Energy Supply LLC [Member] | Recurring [Member] | Cash And Cash Equivalents [Member]
Price risk management assets:
NDT funds	17		14
PPL Energy Supply LLC [Member] | Recurring [Member] | United States Large Cap Equity Securities [Member]
Price risk management assets:
NDT funds	582		547
PPL Energy Supply LLC [Member] | Recurring [Member] | United States Mid Small Cap Equity Securities [Member]
Price risk management assets:
NDT funds	83		81
PPL Energy Supply LLC [Member] | Recurring [Member] | United States Treasury Debt Securities [Member]
Price risk management assets:
NDT funds	98		95
PPL Energy Supply LLC [Member] | Recurring [Member] | United States Government Sponsored Agency Debt Securities [Member]
Price risk management assets:
NDT funds	6		6
PPL Energy Supply LLC [Member] | Recurring [Member] | Municipality Debt Securities [Member]
Price risk management assets:
NDT funds	77		77
PPL Energy Supply LLC [Member] | Recurring [Member] | Investment Grade Corporate Debt Securities [Member]
Price risk management assets:
NDT funds	40		38
PPL Energy Supply LLC [Member] | Recurring [Member] | Other Debt Securities [Member]
Price risk management assets:
NDT funds	6		5
PPL Energy Supply LLC [Member] | Recurring [Member] | Receivables Payables Net [Member]
Price risk management assets:
NDT funds	2		1
PPL Energy Supply LLC [Member] | Recurring [Member] | Level 1 [Member]
Assets
Cash and cash equivalents	194		239
Restricted cash and cash equivalents	284	[1]	85	[1]
Price risk management assets:
Energy commodities assets	4		3
Total price risk management assets	4		3
NDT funds	582		550
Auction rate securities	0		0
Total assets	1,064		877
Price risk management liabilities:
Energy commodities liabilities	2		4
Total price risk management liabilities	2		4
PPL Energy Supply LLC [Member] | Recurring [Member] | Level 1 [Member] | Cash And Cash Equivalents [Member]
Price risk management assets:
NDT funds	17		14
PPL Energy Supply LLC [Member] | Recurring [Member] | Level 1 [Member] | United States Large Cap Equity Securities [Member]
Price risk management assets:
NDT funds	432		409
PPL Energy Supply LLC [Member] | Recurring [Member] | Level 1 [Member] | United States Mid Small Cap Equity Securities [Member]
Price risk management assets:
NDT funds	35		33
PPL Energy Supply LLC [Member] | Recurring [Member] | Level 1 [Member] | United States Treasury Debt Securities [Member]
Price risk management assets:
NDT funds	98		95
PPL Energy Supply LLC [Member] | Recurring [Member] | Level 1 [Member] | United States Government Sponsored Agency Debt Securities [Member]
Price risk management assets:
NDT funds	0		0
PPL Energy Supply LLC [Member] | Recurring [Member] | Level 1 [Member] | Municipality Debt Securities [Member]
Price risk management assets:
NDT funds	0		0
PPL Energy Supply LLC [Member] | Recurring [Member] | Level 1 [Member] | Investment Grade Corporate Debt Securities [Member]
Price risk management assets:
NDT funds	0		0
PPL Energy Supply LLC [Member] | Recurring [Member] | Level 1 [Member] | Other Debt Securities [Member]
Price risk management assets:
NDT funds	0		0
PPL Energy Supply LLC [Member] | Recurring [Member] | Level 1 [Member] | Receivables Payables Net [Member]
Price risk management assets:
NDT funds	0		(1)
PPL Energy Supply LLC [Member] | Recurring [Member] | Level 2 [Member]
Assets
Cash and cash equivalents	0		0
Restricted cash and cash equivalents	0		0
Price risk management assets:
Energy commodities assets	945		1,123
Total price risk management assets	945		1,123
NDT funds	329		314
Auction rate securities	0		0
Total assets	1,274		1,437
Price risk management liabilities:
Energy commodities liabilities	1,063		1,028
Total price risk management liabilities	1,063		1,028
PPL Energy Supply LLC [Member] | Recurring [Member] | Level 2 [Member] | Cash And Cash Equivalents [Member]
Price risk management assets:
NDT funds	0		0
PPL Energy Supply LLC [Member] | Recurring [Member] | Level 2 [Member] | United States Large Cap Equity Securities [Member]
Price risk management assets:
NDT funds	150		138
PPL Energy Supply LLC [Member] | Recurring [Member] | Level 2 [Member] | United States Mid Small Cap Equity Securities [Member]
Price risk management assets:
NDT funds	48		48
PPL Energy Supply LLC [Member] | Recurring [Member] | Level 2 [Member] | United States Treasury Debt Securities [Member]
Price risk management assets:
NDT funds	0		0
PPL Energy Supply LLC [Member] | Recurring [Member] | Level 2 [Member] | United States Government Sponsored Agency Debt Securities [Member]
Price risk management assets:
NDT funds	6		6
PPL Energy Supply LLC [Member] | Recurring [Member] | Level 2 [Member] | Municipality Debt Securities [Member]
Price risk management assets:
NDT funds	77		77
PPL Energy Supply LLC [Member] | Recurring [Member] | Level 2 [Member] | Investment Grade Corporate Debt Securities [Member]
Price risk management assets:
NDT funds	40		38
PPL Energy Supply LLC [Member] | Recurring [Member] | Level 2 [Member] | Other Debt Securities [Member]
Price risk management assets:
NDT funds	6		5
PPL Energy Supply LLC [Member] | Recurring [Member] | Level 2 [Member] | Receivables Payables Net [Member]
Price risk management assets:
NDT funds	2		2
PPL Energy Supply LLC [Member] | Recurring [Member] | Level 3 [Member]
Assets
Cash and cash equivalents	0		0
Restricted cash and cash equivalents	0		0
Price risk management assets:
Energy commodities assets	92		62
Total price risk management assets	92		62
NDT funds	0		0
Auction rate securities	10	[2]	16	[2]
Total assets	102		78
Price risk management liabilities:
Energy commodities liabilities	72		38
Total price risk management liabilities	72		38
PPL Energy Supply LLC [Member] | Recurring [Member] | Level 3 [Member] | Cash And Cash Equivalents [Member]
Price risk management assets:
NDT funds	0		0
PPL Energy Supply LLC [Member] | Recurring [Member] | Level 3 [Member] | United States Large Cap Equity Securities [Member]
Price risk management assets:
NDT funds	0		0
PPL Energy Supply LLC [Member] | Recurring [Member] | Level 3 [Member] | United States Mid Small Cap Equity Securities [Member]
Price risk management assets:
NDT funds	0		0
PPL Energy Supply LLC [Member] | Recurring [Member] | Level 3 [Member] | United States Treasury Debt Securities [Member]
Price risk management assets:
NDT funds	0		0
PPL Energy Supply LLC [Member] | Recurring [Member] | Level 3 [Member] | United States Government Sponsored Agency Debt Securities [Member]
Price risk management assets:
NDT funds	0		0
PPL Energy Supply LLC [Member] | Recurring [Member] | Level 3 [Member] | Municipality Debt Securities [Member]
Price risk management assets:
NDT funds	0		0
PPL Energy Supply LLC [Member] | Recurring [Member] | Level 3 [Member] | Investment Grade Corporate Debt Securities [Member]
Price risk management assets:
NDT funds	0		0
PPL Energy Supply LLC [Member] | Recurring [Member] | Level 3 [Member] | Other Debt Securities [Member]
Price risk management assets:
NDT funds	0		0
PPL Energy Supply LLC [Member] | Recurring [Member] | Level 3 [Member] | Receivables Payables Net [Member]
Price risk management assets:
NDT funds	0		0
PPL Electric Utilities Corp [Member] | Recurring [Member]
Assets
Cash and cash equivalents	111		25
Restricted cash and cash equivalents	3	[3]	12	[3]
Price risk management assets:
Total assets	114		37
PPL Electric Utilities Corp [Member] | Recurring [Member] | Level 1 [Member]
Assets
Cash and cash equivalents	111		25
Restricted cash and cash equivalents	3	[3]	12	[3]
Price risk management assets:
Total assets	114		37
PPL Electric Utilities Corp [Member] | Recurring [Member] | Level 2 [Member]
Assets
Cash and cash equivalents	0		0
Restricted cash and cash equivalents	0		0
Price risk management assets:
Total assets	0		0
PPL Electric Utilities Corp [Member] | Recurring [Member] | Level 3 [Member]
Assets
Cash and cash equivalents	0		0
Restricted cash and cash equivalents	0		0
Price risk management assets:
Total assets	0		0
LG And E And KU Energy LLC [Member] | Recurring [Member]
Assets
Cash and cash equivalents	47		35
Price risk management assets:
Interest rate swaps assets	6		0
Cash collateral posted to counterparties	20	[4]	22	[4]
Total assets	73		57
Price risk management liabilities:
Interest rate swaps liabilities	46		36
Total price risk management liabilities	46		36
LG And E And KU Energy LLC [Member] | Recurring [Member] | Level 1 [Member]
Assets
Cash and cash equivalents	47		35
Price risk management assets:
Interest rate swaps assets	0		0
Cash collateral posted to counterparties	20	[4]	22	[4]
Total assets	67		57
Price risk management liabilities:
Interest rate swaps liabilities	0		0
Total price risk management liabilities	0		0
LG And E And KU Energy LLC [Member] | Recurring [Member] | Level 2 [Member]
Assets
Cash and cash equivalents	0		0
Price risk management assets:
Interest rate swaps assets	6		0
Cash collateral posted to counterparties	0		0
Total assets	6		0
Price risk management liabilities:
Interest rate swaps liabilities	46		36
Total price risk management liabilities	46		36
LG And E And KU Energy LLC [Member] | Recurring [Member] | Level 3 [Member]
Assets
Cash and cash equivalents	0		0
Price risk management assets:
Interest rate swaps assets	0		0
Cash collateral posted to counterparties	0		0
Total assets	0		0
Price risk management liabilities:
Interest rate swaps liabilities	0		0
Total price risk management liabilities	0		0
Louisville Gas And Electric Co [Member] | Recurring [Member]
Assets
Cash and cash equivalents	25		8
Price risk management assets:
Interest rate swaps assets	3		0
Cash collateral posted to counterparties	20	[4]	22	[4]
Total assets	48		30
Price risk management liabilities:
Interest rate swaps liabilities	44		36
Total price risk management liabilities	44		36
Louisville Gas And Electric Co [Member] | Recurring [Member] | Level 1 [Member]
Assets
Cash and cash equivalents	25		8
Price risk management assets:
Interest rate swaps assets	0		0
Cash collateral posted to counterparties	20	[4]	22	[4]
Total assets	45		30
Price risk management liabilities:
Interest rate swaps liabilities	0		0
Total price risk management liabilities	0		0
Louisville Gas And Electric Co [Member] | Recurring [Member] | Level 2 [Member]
Assets
Cash and cash equivalents	0		0
Price risk management assets:
Interest rate swaps assets	3		0
Cash collateral posted to counterparties	0		0
Total assets	3		0
Price risk management liabilities:
Interest rate swaps liabilities	44		36
Total price risk management liabilities	44		36
Louisville Gas And Electric Co [Member] | Recurring [Member] | Level 3 [Member]
Assets
Cash and cash equivalents	0		0
Price risk management assets:
Interest rate swaps assets	0		0
Cash collateral posted to counterparties	0		0
Total assets	0		0
Price risk management liabilities:
Interest rate swaps liabilities	0		0
Total price risk management liabilities	0		0
Kentucky Utilities Co [Member] | Recurring [Member]
Assets
Cash and cash equivalents	22		21
Price risk management assets:
Interest rate swaps assets	3		0
Total assets	25		21
Price risk management liabilities:
Interest rate swaps liabilities	2		0
Total price risk management liabilities	2		0
Kentucky Utilities Co [Member] | Recurring [Member] | Level 1 [Member]
Assets
Cash and cash equivalents	22		21
Price risk management assets:
Interest rate swaps assets	0		0
Total assets	22		21
Price risk management liabilities:
Interest rate swaps liabilities	0		0
Total price risk management liabilities	0		0
Kentucky Utilities Co [Member] | Recurring [Member] | Level 2 [Member]
Assets
Cash and cash equivalents	0		0
Price risk management assets:
Interest rate swaps assets	3		0
Total assets	3		0
Price risk management liabilities:
Interest rate swaps liabilities	2		0
Total price risk management liabilities	2		0
Kentucky Utilities Co [Member] | Recurring [Member] | Level 3 [Member]
Assets
Cash and cash equivalents	0		0
Price risk management assets:
Interest rate swaps assets	0		0
Total assets	0		0
Price risk management liabilities:
Interest rate swaps liabilities	0		0
Total price risk management liabilities	$ 0		$ 0

[1] Current portion is included in "Restricted cash and cash equivalents" and long-term portion is included in "Other noncurrent assets" on the Balance Sheets.

[2] Included in "Other investments" on the Balance Sheets.

[3] Current portion is included in "Other current assets" and long-term portion is included in "Other noncurrent assets" on the Balance Sheets.

[4] Included in "Other noncurrent assets" on the Balance Sheets. Represents cash collateral posted to offset the exposure with counterparties related to certain interest rate swaps under master netting arrangements that are not offset.