Fair Value Measurements (Assets and Liabilities Measured on Recurring Basis Table) (Details) - Recurring [Member] - USD ($) $ in Millions		Sep. 30, 2015		Dec. 31, 2014
Assets
Cash and cash equivalents		$ 981		$ 1,399
Short-term investments		0		120
Restricted cash and cash equivalents	[1]	36		31
Price risk management assets:
Interest rate swaps assets		1	[2]	0
Foreign currency contracts assets	[2]	169		130
Cross-currency swaps assets	[2]	61		29
Total price risk management assets	[2]	231		159
Auction rate securities	[3]	1		2
Total assets		1,249		1,711
Price risk management liabilities:
Interest rate swaps liabilities	[2]	82		156
Foreign currency contracts liabilities	[2]	7		2
Cross-currency swaps liabilities		0		3	[2]
Total price risk management liabilities	[2]	89		161
Level 1 [Member]
Assets
Cash and cash equivalents		981		1,399
Short-term investments		0		120
Restricted cash and cash equivalents	[1]	36		31
Price risk management assets:
Interest rate swaps assets		0		0
Foreign currency contracts assets		0		0
Cross-currency swaps assets		0		0
Total price risk management assets		0		0
Auction rate securities		0		0
Total assets		1,017		1,550
Price risk management liabilities:
Interest rate swaps liabilities		0		0
Foreign currency contracts liabilities		0		0
Cross-currency swaps liabilities		0		0
Total price risk management liabilities		0		0
Level 2 [Member]
Assets
Cash and cash equivalents		0		0
Short-term investments		0		0
Restricted cash and cash equivalents		0		0
Price risk management assets:
Interest rate swaps assets		1	[2]	0
Foreign currency contracts assets	[2]	169		130
Cross-currency swaps assets	[2]	61		28
Total price risk management assets	[2]	231		158
Auction rate securities		0		0
Total assets		231		158
Price risk management liabilities:
Interest rate swaps liabilities	[2]	82		156
Foreign currency contracts liabilities	[2]	7		2
Cross-currency swaps liabilities		0		3	[2]
Total price risk management liabilities	[2]	89		161
Level 3 [Member]
Assets
Cash and cash equivalents		0		0
Short-term investments		0		0
Restricted cash and cash equivalents		0		0
Price risk management assets:
Interest rate swaps assets		0		0
Foreign currency contracts assets		0		0
Cross-currency swaps assets		0		1	[2]
Total price risk management assets		0		1	[2]
Auction rate securities	[3]	1		2
Total assets		1		3
Price risk management liabilities:
Interest rate swaps liabilities		0		0
Foreign currency contracts liabilities		0		0
Cross-currency swaps liabilities		0		0
Total price risk management liabilities		0		0
PPL Electric Utilities Corp [Member]
Assets
Cash and cash equivalents		26		214
Restricted cash and cash equivalents	[1]	2		3
Price risk management assets:
Total assets		28		217
PPL Electric Utilities Corp [Member] | Level 1 [Member]
Assets
Cash and cash equivalents		26		214
Restricted cash and cash equivalents	[1]	2		3
Price risk management assets:
Total assets		28		217
PPL Electric Utilities Corp [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] | 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]
Assets
Cash and cash equivalents		455		21
Price risk management assets:
Cash collateral posted to counterparties	[4]	10		21
Total assets		465		42
Price risk management liabilities:
Interest rate swaps liabilities		50		114
Total price risk management liabilities		50		114
LG And E And KU Energy LLC [Member] | Level 1 [Member]
Assets
Cash and cash equivalents		455		21
Price risk management assets:
Cash collateral posted to counterparties	[4]	10		21
Total assets		465		42
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] | Level 2 [Member]
Assets
Cash and cash equivalents		0		0
Price risk management assets:
Cash collateral posted to counterparties		0		0
Total assets		0		0
Price risk management liabilities:
Interest rate swaps liabilities		50		114
Total price risk management liabilities		50		114
LG And E And KU Energy LLC [Member] | Level 3 [Member]
Assets
Cash and cash equivalents		0		0
Price risk management assets:
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]
Assets
Cash and cash equivalents		180		10
Price risk management assets:
Cash collateral posted to counterparties	[4]	10		21
Total assets		190		31
Price risk management liabilities:
Interest rate swaps liabilities		50		81
Total price risk management liabilities		50		81
Louisville Gas And Electric Co [Member] | Level 1 [Member]
Assets
Cash and cash equivalents		180		10
Price risk management assets:
Cash collateral posted to counterparties	[4]	10		21
Total assets		190		31
Price risk management liabilities:
Interest rate swaps liabilities		0		0
Total price risk management liabilities		0		0
Louisville Gas And Electric Co [Member] | Level 2 [Member]
Assets
Cash and cash equivalents		0		0
Price risk management assets:
Cash collateral posted to counterparties		0		0
Total assets		0		0
Price risk management liabilities:
Interest rate swaps liabilities		50		81
Total price risk management liabilities		50		81
Louisville Gas And Electric Co [Member] | Level 3 [Member]
Assets
Cash and cash equivalents		0		0
Price risk management assets:
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]
Assets
Cash and cash equivalents		275		11
Price risk management assets:
Total assets		275		11
Price risk management liabilities:
Interest rate swaps liabilities		0		33
Total price risk management liabilities		0		33
Kentucky Utilities Co [Member] | Level 1 [Member]
Assets
Cash and cash equivalents		275		11
Price risk management assets:
Total assets		275		11
Price risk management liabilities:
Interest rate swaps liabilities		0		0
Total price risk management liabilities		0		0
Kentucky Utilities Co [Member] | Level 2 [Member]
Assets
Cash and cash equivalents		0		0
Price risk management assets:
Total assets		0		0
Price risk management liabilities:
Interest rate swaps liabilities		0		33
Total price risk management liabilities		0		33
Kentucky Utilities Co [Member] | Level 3 [Member]
Assets
Cash and cash equivalents		0		0
Price risk management assets:
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 "Other current assets" and long-term portion is included in "Other noncurrent assets" on the Balance Sheets.

[2] Included in “Other current assets”, “Other current liabilities”, “Other noncurrent assets” and “Other deferred credits and noncurrent liabilities” on the Balance Sheets.

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

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