Fair Value Measurements and Credit Concentration (Assets and Liabilities Measured on Recurring Basis Table) (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2013		Dec. 31, 2012
Price risk management liabilities:
Total price risk management liabilities	$ 1,361		$ 1,694
Recurring [Member]
Assets
Cash and cash equivalents	1,291		901
Restricted cash and cash equivalents	120	[1]	135	[1]
Price risk management assets:
Energy commodities assets	1,480		2,068
Interest rate swaps assets	86		15
Foreign currency contracts assets	1
Cross-currency swaps assets	28		14
Total price risk management assets	1,595		2,097
NDT funds	804		712
Auction rate securities	19	[2]	19	[2]
Total assets	3,829		3,864
Price risk management liabilities:
Energy commodities liabilities	1,235		1,566
Interest rate swaps liabilities	58		80
Foreign currency contracts liabilities	67		44
Cross-currency swaps liabilities	1		4
Total price risk management liabilities	1,361		1,694
Recurring [Member] | Cash And Cash Equivalents [Member]
Price risk management assets:
NDT funds	14		11
Recurring [Member] | United States Large Cap Equity Securities [Member]
Price risk management assets:
NDT funds	494		412
Recurring [Member] | United States Mid Small Cap Equity Securities [Member]
Price risk management assets:
NDT funds	74		60
Recurring [Member] | United States Treasury Debt Securities [Member]
Price risk management assets:
NDT funds	96		95
Recurring [Member] | United States Government Sponsored Agency Debt Securities [Member]
Price risk management assets:
NDT funds	6		9
Recurring [Member] | Municipality Debt Securities [Member]
Price risk management assets:
NDT funds	75		82
Recurring [Member] | Investment Grade Corporate Debt Securities [Member]
Price risk management assets:
NDT funds	40		40
Recurring [Member] | Other Debt Securities [Member]
Price risk management assets:
NDT funds	3		3
Recurring [Member] | Receivables Payables Net [Member]
Price risk management assets:
NDT funds	2
Recurring [Member] | Level 1 [Member]
Assets
Cash and cash equivalents	1,291		901
Restricted cash and cash equivalents	120	[1]	135	[1]
Price risk management assets:
Energy commodities assets	7		2
Interest rate swaps assets
Foreign currency contracts assets
Cross-currency swaps assets
Total price risk management assets	7		2
NDT funds	509		437
Auction rate securities
Total assets	1,927		1,475
Price risk management liabilities:
Energy commodities liabilities	4		2
Interest rate swaps liabilities
Foreign currency contracts liabilities
Cross-currency swaps liabilities
Total price risk management liabilities	4		2
Recurring [Member] | Level 1 [Member] | Cash And Cash Equivalents [Member]
Price risk management assets:
NDT funds	14		11
Recurring [Member] | Level 1 [Member] | United States Large Cap Equity Securities [Member]
Price risk management assets:
NDT funds	369		308
Recurring [Member] | Level 1 [Member] | United States Mid Small Cap Equity Securities [Member]
Price risk management assets:
NDT funds	30		25
Recurring [Member] | Level 1 [Member] | United States Treasury Debt Securities [Member]
Price risk management assets:
NDT funds	96		95
Recurring [Member] | Level 1 [Member] | United States Government Sponsored Agency Debt Securities [Member]
Price risk management assets:
NDT funds
Recurring [Member] | Level 1 [Member] | Municipality Debt Securities [Member]
Price risk management assets:
NDT funds
Recurring [Member] | Level 1 [Member] | Investment Grade Corporate Debt Securities [Member]
Price risk management assets:
NDT funds
Recurring [Member] | Level 1 [Member] | Other Debt Securities [Member]
Price risk management assets:
NDT funds
Recurring [Member] | Level 1 [Member] | Receivables Payables Net [Member]
Price risk management assets:
NDT funds			(2)
Recurring [Member] | Level 2 [Member]
Assets
Cash and cash equivalents
Restricted cash and cash equivalents
Price risk management assets:
Energy commodities assets	1,421		2,037
Interest rate swaps assets	86		15
Foreign currency contracts assets	1
Cross-currency swaps assets	28		13
Total price risk management assets	1,536		2,065
NDT funds	295		275
Auction rate securities			3	[2]
Total assets	1,831		2,343
Price risk management liabilities:
Energy commodities liabilities	1,226		1,557
Interest rate swaps liabilities	58		80
Foreign currency contracts liabilities	67		44
Cross-currency swaps liabilities	1		4
Total price risk management liabilities	1,352		1,685
Recurring [Member] | Level 2 [Member] | Cash And Cash Equivalents [Member]
Price risk management assets:
NDT funds
Recurring [Member] | Level 2 [Member] | United States Large Cap Equity Securities [Member]
Price risk management assets:
NDT funds	125		104
Recurring [Member] | Level 2 [Member] | United States Mid Small Cap Equity Securities [Member]
Price risk management assets:
NDT funds	44		35
Recurring [Member] | Level 2 [Member] | United States Treasury Debt Securities [Member]
Price risk management assets:
NDT funds
Recurring [Member] | Level 2 [Member] | United States Government Sponsored Agency Debt Securities [Member]
Price risk management assets:
NDT funds	6		9
Recurring [Member] | Level 2 [Member] | Municipality Debt Securities [Member]
Price risk management assets:
NDT funds	75		82
Recurring [Member] | Level 2 [Member] | Investment Grade Corporate Debt Securities [Member]
Price risk management assets:
NDT funds	40		40
Recurring [Member] | Level 2 [Member] | Other Debt Securities [Member]
Price risk management assets:
NDT funds	3		3
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
Restricted cash and cash equivalents
Price risk management assets:
Energy commodities assets	52		29
Interest rate swaps assets
Foreign currency contracts assets
Cross-currency swaps assets			1
Total price risk management assets	52		30
NDT funds
Auction rate securities	19	[2]	16	[2]
Total assets	71		46
Price risk management liabilities:
Energy commodities liabilities	5		7
Interest rate swaps liabilities
Foreign currency contracts liabilities
Cross-currency swaps liabilities
Total price risk management liabilities	5		7
Recurring [Member] | Level 3 [Member] | Cash And Cash Equivalents [Member]
Price risk management assets:
NDT funds
Recurring [Member] | Level 3 [Member] | United States Large Cap Equity Securities [Member]
Price risk management assets:
NDT funds
Recurring [Member] | Level 3 [Member] | United States Mid Small Cap Equity Securities [Member]
Price risk management assets:
NDT funds
Recurring [Member] | Level 3 [Member] | United States Treasury Debt Securities [Member]
Price risk management assets:
NDT funds
Recurring [Member] | Level 3 [Member] | United States Government Sponsored Agency Debt Securities [Member]
Price risk management assets:
NDT funds
Recurring [Member] | Level 3 [Member] | Municipality Debt Securities [Member]
Price risk management assets:
NDT funds
Recurring [Member] | Level 3 [Member] | Investment Grade Corporate Debt Securities [Member]
Price risk management assets:
NDT funds
Recurring [Member] | Level 3 [Member] | Other Debt Securities [Member]
Price risk management assets:
NDT funds
Recurring [Member] | Level 3 [Member] | Receivables Payables Net [Member]
Price risk management assets:
NDT funds
PPL Energy Supply LLC [Member] | Recurring [Member]
Assets
Cash and cash equivalents	551		413
Restricted cash and cash equivalents	54	[1]	63	[1]
Price risk management assets:
Energy commodities assets	1,480		2,068
Total price risk management assets	1,480		2,068
NDT funds	804		712
Auction rate securities	16	[2]	16	[2]
Total assets	2,905		3,272
Price risk management liabilities:
Energy commodities liabilities	1,235		1,566
Total price risk management liabilities	1,235		1,566
PPL Energy Supply LLC [Member] | Recurring [Member] | Cash And Cash Equivalents [Member]
Price risk management assets:
NDT funds	14		11
PPL Energy Supply LLC [Member] | Recurring [Member] | United States Large Cap Equity Securities [Member]
Price risk management assets:
NDT funds	494		412
PPL Energy Supply LLC [Member] | Recurring [Member] | United States Mid Small Cap Equity Securities [Member]
Price risk management assets:
NDT funds	74		60
PPL Energy Supply LLC [Member] | Recurring [Member] | United States Treasury Debt Securities [Member]
Price risk management assets:
NDT funds	96		95
PPL Energy Supply LLC [Member] | Recurring [Member] | United States Government Sponsored Agency Debt Securities [Member]
Price risk management assets:
NDT funds	6		9
PPL Energy Supply LLC [Member] | Recurring [Member] | Municipality Debt Securities [Member]
Price risk management assets:
NDT funds	75		82
PPL Energy Supply LLC [Member] | Recurring [Member] | Investment Grade Corporate Debt Securities [Member]
Price risk management assets:
NDT funds	40		40
PPL Energy Supply LLC [Member] | Recurring [Member] | Other Debt Securities [Member]
Price risk management assets:
NDT funds	3		3
PPL Energy Supply LLC [Member] | Recurring [Member] | Receivables Payables Net [Member]
Price risk management assets:
NDT funds	2
PPL Energy Supply LLC [Member] | Recurring [Member] | Level 1 [Member]
Assets
Cash and cash equivalents	551		413
Restricted cash and cash equivalents	54	[1]	63	[1]
Price risk management assets:
Energy commodities assets	7		2
Total price risk management assets	7		2
NDT funds	509		437
Auction rate securities
Total assets	1,121		915
Price risk management liabilities:
Energy commodities liabilities	4		2
Total price risk management liabilities	4		2
PPL Energy Supply LLC [Member] | Recurring [Member] | Level 1 [Member] | Cash And Cash Equivalents [Member]
Price risk management assets:
NDT funds	14		11
PPL Energy Supply LLC [Member] | Recurring [Member] | Level 1 [Member] | United States Large Cap Equity Securities [Member]
Price risk management assets:
NDT funds	369		308
PPL Energy Supply LLC [Member] | Recurring [Member] | Level 1 [Member] | United States Mid Small Cap Equity Securities [Member]
Price risk management assets:
NDT funds	30		25
PPL Energy Supply LLC [Member] | Recurring [Member] | Level 1 [Member] | United States Treasury Debt Securities [Member]
Price risk management assets:
NDT funds	96		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
PPL Energy Supply LLC [Member] | Recurring [Member] | Level 1 [Member] | Municipality Debt Securities [Member]
Price risk management assets:
NDT funds
PPL Energy Supply LLC [Member] | Recurring [Member] | Level 1 [Member] | Investment Grade Corporate Debt Securities [Member]
Price risk management assets:
NDT funds
PPL Energy Supply LLC [Member] | Recurring [Member] | Level 1 [Member] | Other Debt Securities [Member]
Price risk management assets:
NDT funds
PPL Energy Supply LLC [Member] | Recurring [Member] | Level 1 [Member] | Receivables Payables Net [Member]
Price risk management assets:
NDT funds			(2)
PPL Energy Supply LLC [Member] | Recurring [Member] | Level 2 [Member]
Assets
Cash and cash equivalents
Restricted cash and cash equivalents
Price risk management assets:
Energy commodities assets	1,421		2,037
Total price risk management assets	1,421		2,037
NDT funds	295		275
Auction rate securities			3	[2]
Total assets	1,716		2,315
Price risk management liabilities:
Energy commodities liabilities	1,226		1,557
Total price risk management liabilities	1,226		1,557
PPL Energy Supply LLC [Member] | Recurring [Member] | Level 2 [Member] | Cash And Cash Equivalents [Member]
Price risk management assets:
NDT funds
PPL Energy Supply LLC [Member] | Recurring [Member] | Level 2 [Member] | United States Large Cap Equity Securities [Member]
Price risk management assets:
NDT funds	125		104
PPL Energy Supply LLC [Member] | Recurring [Member] | Level 2 [Member] | United States Mid Small Cap Equity Securities [Member]
Price risk management assets:
NDT funds	44		35
PPL Energy Supply LLC [Member] | Recurring [Member] | Level 2 [Member] | United States Treasury Debt Securities [Member]
Price risk management assets:
NDT funds
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		9
PPL Energy Supply LLC [Member] | Recurring [Member] | Level 2 [Member] | Municipality Debt Securities [Member]
Price risk management assets:
NDT funds	75		82
PPL Energy Supply LLC [Member] | Recurring [Member] | Level 2 [Member] | Investment Grade Corporate Debt Securities [Member]
Price risk management assets:
NDT funds	40		40
PPL Energy Supply LLC [Member] | Recurring [Member] | Level 2 [Member] | Other Debt Securities [Member]
Price risk management assets:
NDT funds	3		3
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
Restricted cash and cash equivalents
Price risk management assets:
Energy commodities assets	52		29
Total price risk management assets	52		29
NDT funds
Auction rate securities	16	[2]	13	[2]
Total assets	68		42
Price risk management liabilities:
Energy commodities liabilities	5		7
Total price risk management liabilities	5		7
PPL Energy Supply LLC [Member] | Recurring [Member] | Level 3 [Member] | Cash And Cash Equivalents [Member]
Price risk management assets:
NDT funds
PPL Energy Supply LLC [Member] | Recurring [Member] | Level 3 [Member] | United States Large Cap Equity Securities [Member]
Price risk management assets:
NDT funds
PPL Energy Supply LLC [Member] | Recurring [Member] | Level 3 [Member] | United States Mid Small Cap Equity Securities [Member]
Price risk management assets:
NDT funds
PPL Energy Supply LLC [Member] | Recurring [Member] | Level 3 [Member] | United States Treasury Debt Securities [Member]
Price risk management assets:
NDT funds
PPL Energy Supply LLC [Member] | Recurring [Member] | Level 3 [Member] | United States Government Sponsored Agency Debt Securities [Member]
Price risk management assets:
NDT funds
PPL Energy Supply LLC [Member] | Recurring [Member] | Level 3 [Member] | Municipality Debt Securities [Member]
Price risk management assets:
NDT funds
PPL Energy Supply LLC [Member] | Recurring [Member] | Level 3 [Member] | Investment Grade Corporate Debt Securities [Member]
Price risk management assets:
NDT funds
PPL Energy Supply LLC [Member] | Recurring [Member] | Level 3 [Member] | Other Debt Securities [Member]
Price risk management assets:
NDT funds
PPL Energy Supply LLC [Member] | Recurring [Member] | Level 3 [Member] | Receivables Payables Net [Member]
Price risk management assets:
NDT funds
PPL Electric Utilities Corp [Member] | Recurring [Member]
Assets
Cash and cash equivalents	225		140
Restricted cash and cash equivalents	12	[3]	13	[3]
Price risk management assets:
Total assets	237		153
PPL Electric Utilities Corp [Member] | Recurring [Member] | Level 1 [Member]
Assets
Cash and cash equivalents	225		140
Restricted cash and cash equivalents	12	[3]	13	[3]
Price risk management assets:
Total assets	237		153
PPL Electric Utilities Corp [Member] | Recurring [Member] | Level 2 [Member]
Assets
Cash and cash equivalents
Restricted cash and cash equivalents
Price risk management assets:
Total assets
PPL Electric Utilities Corp [Member] | Recurring [Member] | Level 3 [Member]
Assets
Cash and cash equivalents
Restricted cash and cash equivalents
Price risk management assets:
Total assets
LG And E And KU Energy LLC [Member] | Recurring [Member]
Assets
Cash and cash equivalents	21		43
Restricted cash and cash equivalents	22	[4]	32	[4]
Price risk management assets:
Interest rate swaps assets			14
Total price risk management assets			14
Total assets	43		89
Price risk management liabilities:
Interest rate swaps liabilities	55		58
Total price risk management liabilities	55		58
LG And E And KU Energy LLC [Member] | Recurring [Member] | Level 1 [Member]
Assets
Cash and cash equivalents	21		43
Restricted cash and cash equivalents	22	[4]	32	[4]
Price risk management assets:
Interest rate swaps assets
Total price risk management assets
Total assets	43		75
Price risk management liabilities:
Interest rate swaps liabilities
Total price risk management liabilities
LG And E And KU Energy LLC [Member] | Recurring [Member] | Level 2 [Member]
Assets
Cash and cash equivalents
Restricted cash and cash equivalents
Price risk management assets:
Interest rate swaps assets			14
Total price risk management assets			14
Total assets			14
Price risk management liabilities:
Interest rate swaps liabilities	55		58
Total price risk management liabilities	55		58
LG And E And KU Energy LLC [Member] | Recurring [Member] | Level 3 [Member]
Assets
Cash and cash equivalents
Restricted cash and cash equivalents
Price risk management assets:
Interest rate swaps assets
Total price risk management assets
Total assets
Price risk management liabilities:
Interest rate swaps liabilities
Total price risk management liabilities
Louisville Gas And Electric Co [Member] | Recurring [Member]
Assets
Cash and cash equivalents	12		22
Restricted cash and cash equivalents	22	[4]	32	[4]
Price risk management assets:
Interest rate swaps assets			7
Total price risk management assets			7
Total assets	34		61
Price risk management liabilities:
Interest rate swaps liabilities	48		58
Total price risk management liabilities	48		58
Louisville Gas And Electric Co [Member] | Recurring [Member] | Level 1 [Member]
Assets
Cash and cash equivalents	12		22
Restricted cash and cash equivalents	22	[4]	32	[4]
Price risk management assets:
Interest rate swaps assets
Total price risk management assets
Total assets	34		54
Price risk management liabilities:
Interest rate swaps liabilities
Total price risk management liabilities
Louisville Gas And Electric Co [Member] | Recurring [Member] | Level 2 [Member]
Assets
Cash and cash equivalents
Restricted cash and cash equivalents
Price risk management assets:
Interest rate swaps assets			7
Total price risk management assets			7
Total assets			7
Price risk management liabilities:
Interest rate swaps liabilities	48		58
Total price risk management liabilities	48		58
Louisville Gas And Electric Co [Member] | Recurring [Member] | Level 3 [Member]
Assets
Cash and cash equivalents
Restricted cash and cash equivalents
Price risk management assets:
Interest rate swaps assets
Total price risk management assets
Total assets
Price risk management liabilities:
Interest rate swaps liabilities
Total price risk management liabilities
Kentucky Utilities Co [Member]
Price risk management liabilities:
Interest rate swaps liabilities
Kentucky Utilities Co [Member] | Recurring [Member]
Assets
Cash and cash equivalents	9		21
Price risk management assets:
Interest rate swaps assets			7
Total price risk management assets			7
Total assets	9		28
Price risk management liabilities:
Interest rate swaps liabilities	7
Total price risk management liabilities	7
Kentucky Utilities Co [Member] | Recurring [Member] | Level 1 [Member]
Assets
Cash and cash equivalents	9		21
Price risk management assets:
Interest rate swaps assets
Total price risk management assets
Total assets	9		21
Price risk management liabilities:
Interest rate swaps liabilities
Total price risk management liabilities
Kentucky Utilities Co [Member] | Recurring [Member] | Level 2 [Member]
Assets
Cash and cash equivalents
Price risk management assets:
Interest rate swaps assets			7
Total price risk management assets			7
Total assets			7
Price risk management liabilities:
Interest rate swaps liabilities	7
Total price risk management liabilities	7
Kentucky Utilities Co [Member] | Recurring [Member] | Level 3 [Member]
Assets
Cash and cash equivalents
Price risk management assets:
Interest rate swaps assets
Total price risk management assets
Total assets
Price risk management liabilities:
Interest rate swaps liabilities
Total price risk management liabilities

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

[4] Included in "Other noncurrent assets" on the Balance Sheets.