Summary of Significant Accounting Policies (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017	Dec. 31, 2016
Summary Of Significant Accounting Policies [Line Items]
Defined Benefit Plan, Net Periodic Benefit (Cost) Credit- Non Service	$ 66	$ 44	$ 134	$ 82
Reconciliation of Cash, Cash Equivalents and Restricted Cash from the Balance Sheet to Cash Flow Statement [Line Items]
Cash and cash equivalents	852		852		$ 485
Restricted Cash, Current	3		3		3
Restricted Cash, Noncurrent	20		20		23
Cash, Cash Equivalents and Restricted Cash	875	490	875	490	511	$ 367
Income Statement impact of ASU 2017-07 [Member]
Summary Of Significant Accounting Policies [Line Items]
Defined Benefit Plan, Net Periodic Benefit (Cost) Credit- Non Service	6		11
Defined Benefit Plan Net Periodic Benefit (Cost) Credit Non Service, After tax	$ 5		$ 9
Defined Benefit Plan Net Periodic Benefit (Cost) Credit NonService, Per Share	$ 0.01		$ 0.01
Impact of adoption of ASU 2017-07 [Member]
Summary Of Significant Accounting Policies [Line Items]
Defined Benefit Plan, Net Periodic Benefit (Cost) Credit- Non Service	$ 66	44	$ 134	82
PPL Electric Utilities Corp [Member]
Summary Of Significant Accounting Policies [Line Items]
Defined Benefit Plan, Net Periodic Benefit (Cost) Credit- Non Service	1	1	3	0
Reconciliation of Cash, Cash Equivalents and Restricted Cash from the Balance Sheet to Cash Flow Statement [Line Items]
Cash and cash equivalents	489		489		49
Restricted Cash, Current	2		2		2
Restricted Cash, Noncurrent	0		0		0
Cash, Cash Equivalents and Restricted Cash	491	61	491	61	51	15
PPL Electric Utilities Corp [Member] | Impact of adoption of ASU 2017-07 [Member]
Summary Of Significant Accounting Policies [Line Items]
Defined Benefit Plan, Net Periodic Benefit (Cost) Credit- Non Service	1	1	3	0
LG And E And KU Energy LLC [Member]
Reconciliation of Cash, Cash Equivalents and Restricted Cash from the Balance Sheet to Cash Flow Statement [Line Items]
Cash and cash equivalents	39	19	39	19	30	13
LG And E And KU Energy LLC [Member] | Impact of adoption of ASU 2017-07 [Member]
Summary Of Significant Accounting Policies [Line Items]
Defined Benefit Plan, Net Periodic Benefit (Cost) Credit- Non Service	0	0	2	(2)
Louisville Gas And Electric Co [Member]
Reconciliation of Cash, Cash Equivalents and Restricted Cash from the Balance Sheet to Cash Flow Statement [Line Items]
Cash and cash equivalents	19	7	19	7	15	5
Louisville Gas And Electric Co [Member] | Impact of adoption of ASU 2017-07 [Member]
Summary Of Significant Accounting Policies [Line Items]
Defined Benefit Plan, Net Periodic Benefit (Cost) Credit- Non Service	(2)	0	(1)	(2)
Kentucky Utilities Co [Member]
Reconciliation of Cash, Cash Equivalents and Restricted Cash from the Balance Sheet to Cash Flow Statement [Line Items]
Cash and cash equivalents	20	12	20	12	$ 15	$ 7
Kentucky Utilities Co [Member] | Impact of adoption of ASU 2017-07 [Member]
Summary Of Significant Accounting Policies [Line Items]
Defined Benefit Plan, Net Periodic Benefit (Cost) Credit- Non Service	$ 1	$ 0	$ 2	$ (1)