Related Party Transactions (Details) - USD ($) $ in Millions	1 Months Ended	3 Months Ended		6 Months Ended		12 Months Ended
	May 31, 2018	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
PPL Electric Utilities Corp [Member] | PPL Services [Member]
Support Costs (Details) [Abstract]
Support cost allocations from subsidiary of parent to registrant		$ 15	$ 44	$ 31	$ 95
PPL Electric Utilities Corp [Member] | PPL EU Services [Member]
Support Costs (Details) [Abstract]
Support cost allocations from subsidiary of parent to registrant		41	15	76	33
PPL Electric Utilities Corp [Member] | PPL Energy Funding [Member]
Intercompany Borrowings (Numeric) [Abstract]
Intercompany note with affiliate maximum borrowing capacity		650		650
Notes receivable from affiliate		0		0		$ 0
Intercompany Note Affiliate Maximum Borrowing Capacity Increase		250		250
LG And E And KU Energy LLC [Member]
Intercompany Borrowings (Numeric) [Abstract]
Notes payable to affiliates		99		99		225
Long-term debt to affiliate		650		650		400
Interest Expense with Affiliate		6	4	11	8
LG And E And KU Energy LLC [Member] | PPL Services [Member]
Support Costs (Details) [Abstract]
Support cost allocations from subsidiary of parent to registrant		7	5	14	11
LG And E And KU Energy LLC [Member] | PPL Energy Funding [Member]
Intercompany Borrowings (Numeric) [Abstract]
Intercompany note with affiliate maximum borrowing capacity		300		300
Notes payable to affiliates		99		$ 99		$ 225
Intercompany borrowings demand note rate on outstanding borrowing				3.50%		2.87%
LG And E And KU Energy LLC [Member] | PPL Affiliate [Member]
Intercompany Borrowings (Numeric) [Abstract]
Intercompany note with affiliate maximum borrowing capacity		300		$ 300
Notes Receivable, Related Parties, Noncurrent		0		$ 0		$ 0
LG And E And KU Energy LLC [Member] | PPL Affiliate [Member]
Intercompany Borrowings (Numeric) [Abstract]
Debt instrument term (in years)				10 years
Long-term debt to affiliate		$ 400		$ 400
Interest rate on ten-year note		3.50%		3.50%
Interest Expense with Affiliate		$ 3	3	$ 7	7
LG And E And KU Energy LLC [Member] | Affiliated Entity [Member]
Intercompany Borrowings (Numeric) [Abstract]
Interest Expense with Affiliate		2		2
LG And E And KU Energy LLC [Member] | Note Payable [Member] | Affiliated Entity [Member]
Intercompany Borrowings (Numeric) [Abstract]
Stated interest rate	4.00%
Maturity date	May 31, 2028
Notes Payable, Noncurrent	$ 250
Louisville Gas And Electric Co [Member] | LKS [Member]
Intercompany Billings by LKS (Details) [Abstract]
Intercompany billings between affiliates		39	38	77	82
Kentucky Utilities Co [Member] | LKS [Member]
Intercompany Billings by LKS (Details) [Abstract]
Intercompany billings between affiliates		$ 43	$ 47	$ 85	$ 91