Summary of Significant Accounting Policies (Details) $ / shares in Units, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2017 USD ($)	Sep. 30, 2017 USD ($)	Jun. 30, 2017 USD ($)	Mar. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Sep. 30, 2016 USD ($)	Jun. 30, 2016 USD ($)	Mar. 31, 2016 USD ($)	Dec. 31, 2017 USD ($) Integer MW	Dec. 31, 2016 USD ($) $ / shares	Dec. 31, 2015 USD ($)
Utility Revenue (Details) [Abstract]
Domestic electric and gas revenue									$ 5,351	$ 5,297	$ 5,239
U.K. operating revenues									2,091	2,207	2,410
Domestic - other									5	13	20
Operating Revenues	$ 1,926	$ 1,845	$ 1,725	$ 1,951	$ 1,832	$ 1,889	$ 1,785	$ 2,011	7,447	7,517	7,669
Restricted Cash and Cash Equivalents (Numeric) [Abstract]
Restricted cash and cash equivalents	26				26				26	26
Property, Plant and Equipment (Numeric) [Abstract]
Interest costs, capitalized during the period									$ 11	11	$ 11
Defined Benefits [Abstract]
Percentage in excess of gains and losses equal to the plan's projected benefit obligation to use accelerated amortization									30.00%
Minimum percentage of gains and losses under the accelerated method that are amortized on a straight line basis									10.00%
Maximum percentage of gains and losses under the accelerated that are amortized on a straight line basis									30.00%
Discount Rate Change For United Kingdom Pension Plans Numeric [Abstract]
Decrease in net periodic defined benefit cost from change in the discount rate										43
Decrease in net periodic defined benefit cost from change in the discount rate, after-tax										$ 34
Decrease in net periodic defined benefit cost from change in the discount rate, per share | $ / shares										$ 0.05
Income Taxes [Abstract]
Minimum percentage to be attained of likelihood of uncertain tax position being realized									50.00%
Fuel, Materials and Supplies (Details) [Abstract]
Fuel, materials and supplies on the Balance Sheet	320				356				$ 320	$ 356
Fuel [Member]
Fuel, Materials and Supplies (Details) [Abstract]
Fuel, materials and supplies on the Balance Sheet	107				158				107	158
Natural Gas Stored Underground [Member]
Fuel, Materials and Supplies (Details) [Abstract]
Fuel, materials and supplies on the Balance Sheet	43				42				43	42
Material And Supplies [Member]
Fuel, Materials and Supplies (Details) [Abstract]
Fuel, materials and supplies on the Balance Sheet	170				156				$ 170	$ 156
Regulated Operations [Member] | Utility Plant [Member]
Depreciation (Details) [Abstract]
Weighted-average rates									2.65%	2.73%	2.57%
Low Carbon Network Fund [Member]
Restricted Cash and Cash Equivalents (Numeric) [Abstract]
Restricted cash and cash equivalents	17				17				$ 17	$ 17
Other Restricted Cash [Member]
Restricted Cash and Cash Equivalents (Numeric) [Abstract]
Restricted cash and cash equivalents	9				9				9	9
Allowance For Doubtful Accounts [Member]
Allowance for Doubtful Accounts (Details) [Roll Forward]
Balance at beginning of period				54				41	54	41	$ 44
Additions charged to income									28	44	49
Additions charged to other accounts									(1)	0	(2)
Deductions									30	31	50
Balance at end of period	51				54				$ 51	54	41
WPD [Member]
Summary of Significant Accounting Policies [Line Items]
Period of lag in reporting results for WPD (in months) | Integer									1
Revenue Recognition (Numeric) [Abstract]
Number of regulatory years later future demand revenue is affected									2 years
Percentage WPD's distribution network operators are able to retain of any under-spends									70.00%
Percentage WPD's distribution network operators bear of any over-spends									70.00%
Period of lag between incentives and penalties are reflected in customers' rates									2 years
Refunded/recovered period of lag for recovery of over and under-recovered amounts arising from 2014/15 onwards									2 years
Previous refunded/recovered period of lag for recovery of over and under-recovered amounts									1 year
LGE [Member] | Ohio Valley Electric Corporation [Member]
Cost Method Investments [Abstract]
Number of electric utilities that are equity owners | Integer									10
Number of companies power is supplied to | Integer									11
Ownership percentage									5.63%
Generation capacity in terms of ownership percentage (in MW) | MW									120
KU [Member] | Ohio Valley Electric Corporation [Member]
Cost Method Investments [Abstract]
Number of electric utilities that are equity owners | Integer									10
Number of companies power is supplied to | Integer									11
Ownership percentage									2.50%
Generation capacity in terms of ownership percentage (in MW) | MW									53
PPL Electric Utilities Corp [Member]
Utility Revenue (Details) [Abstract]
Operating Revenues	575	$ 547	$ 500	573	537	$ 539	$ 495	585	$ 2,195	2,156	$ 2,124
Restricted Cash and Cash Equivalents (Numeric) [Abstract]
Restricted cash and cash equivalents	2				2				$ 2	2
Property, Plant and Equipment (Numeric) [Abstract]
Regulatory Asset Amortization Period									5 years
Defined Benefits [Abstract]
Percentage in excess of gains and losses equal to the plan's projected benefit obligation to use accelerated amortization									30.00%
Minimum percentage of gains and losses under the accelerated method that are amortized on a straight line basis									10.00%
Maximum percentage of gains and losses under the accelerated that are amortized on a straight line basis									30.00%
Income Taxes [Abstract]
Minimum percentage to be attained of likelihood of uncertain tax position being realized									50.00%
Intercompany tax receivables (payables)	61				13				$ 61	$ 13
PPL Electric Utilities Corp [Member] | Regulated Operations [Member] | Utility Plant [Member]
Depreciation (Details) [Abstract]
Weighted-average rates									2.86%	2.63%	2.46%
PPL Electric Utilities Corp [Member] | Low Carbon Network Fund [Member]
Restricted Cash and Cash Equivalents (Numeric) [Abstract]
Restricted cash and cash equivalents	0				0				$ 0	$ 0
PPL Electric Utilities Corp [Member] | Other Restricted Cash [Member]
Restricted Cash and Cash Equivalents (Numeric) [Abstract]
Restricted cash and cash equivalents	2				2				2	2
PPL Electric Utilities Corp [Member] | Allowance For Doubtful Accounts [Member]
Allowance for Doubtful Accounts (Details) [Roll Forward]
Balance at beginning of period				28				16	28	16	$ 17
Additions charged to income									18	35	39
Additions charged to other accounts									0	0	0
Deductions									22	23	40
Balance at end of period	24				28				24	28	16
LG And E And KU Energy LLC [Member]
Utility Revenue (Details) [Abstract]
Operating Revenues									$ 3,156	3,141	$ 3,115
Defined Benefits [Abstract]
Percentage in excess of gains and losses equal to the plan's projected benefit obligation to use accelerated amortization									30.00%
Minimum percentage of gains and losses under the accelerated method that are amortized on a straight line basis									10.00%
Maximum percentage of gains and losses under the accelerated that are amortized on a straight line basis									30.00%
Income Taxes [Abstract]
Minimum percentage to be attained of likelihood of uncertain tax position being realized									50.00%
Intercompany tax receivables (payables)	(23)				1				$ (23)	1
Fuel, Materials and Supplies (Details) [Abstract]
Fuel, materials and supplies on the Balance Sheet	254				297				254	297
LG And E And KU Energy LLC [Member] | Fuel [Member]
Fuel, Materials and Supplies (Details) [Abstract]
Fuel, materials and supplies on the Balance Sheet	107				158				107	158
LG And E And KU Energy LLC [Member] | Natural Gas Stored Underground [Member]
Fuel, Materials and Supplies (Details) [Abstract]
Fuel, materials and supplies on the Balance Sheet	43				42				43	42
LG And E And KU Energy LLC [Member] | Material And Supplies [Member]
Fuel, Materials and Supplies (Details) [Abstract]
Fuel, materials and supplies on the Balance Sheet	104				97				$ 104	$ 97
LG And E And KU Energy LLC [Member] | Regulated Operations [Member] | Utility Plant [Member]
Depreciation (Details) [Abstract]
Weighted-average rates									3.64%	3.69%	3.69%
LG And E And KU Energy LLC [Member] | Allowance For Doubtful Accounts [Member]
Allowance for Doubtful Accounts (Details) [Roll Forward]
Balance at beginning of period				24				23	$ 24	$ 23	$ 25
Additions charged to income									8	8	9
Additions charged to other accounts									(1)	0	(2)
Deductions									6	7	9
Balance at end of period	25				24				$ 25	24	23
LG And E And KU Energy LLC [Member] | LGE [Member] | Ohio Valley Electric Corporation [Member]
Cost Method Investments [Abstract]
Number of electric utilities that are equity owners | Integer									10
Number of companies power is supplied to | Integer									11
Ownership percentage									5.63%
Generation capacity in terms of ownership percentage (in MW) | MW									120
LG And E And KU Energy LLC [Member] | KU [Member] | Ohio Valley Electric Corporation [Member]
Cost Method Investments [Abstract]
Number of electric utilities that are equity owners | Integer									10
Number of companies power is supplied to | Integer									11
Ownership percentage									2.50%
Generation capacity in terms of ownership percentage (in MW) | MW									53
Louisville Gas And Electric Co [Member]
Utility Revenue (Details) [Abstract]
Operating Revenues									$ 1,453	1,430	$ 1,444
Defined Benefits [Abstract]
Percentage in excess of gains and losses equal to the plan's projected benefit obligation to use accelerated amortization									30.00%
Minimum percentage of gains and losses under the accelerated method that are amortized on a straight line basis									10.00%
Maximum percentage of gains and losses under the accelerated that are amortized on a straight line basis									30.00%
Income Taxes [Abstract]
Minimum percentage to be attained of likelihood of uncertain tax position being realized									50.00%
Intercompany tax receivables (payables)	0				(18)				$ 0	(18)
Fuel, Materials and Supplies (Details) [Abstract]
Fuel, materials and supplies on the Balance Sheet	131				143				131	143
Louisville Gas And Electric Co [Member] | Fuel [Member]
Fuel, Materials and Supplies (Details) [Abstract]
Fuel, materials and supplies on the Balance Sheet	45				60				45	60
Louisville Gas And Electric Co [Member] | Natural Gas Stored Underground [Member]
Fuel, Materials and Supplies (Details) [Abstract]
Fuel, materials and supplies on the Balance Sheet	43				42				43	42
Louisville Gas And Electric Co [Member] | Material And Supplies [Member]
Fuel, Materials and Supplies (Details) [Abstract]
Fuel, materials and supplies on the Balance Sheet	43				41				$ 43	$ 41
Louisville Gas And Electric Co [Member] | Regulated Operations [Member] | Utility Plant [Member]
Depreciation (Details) [Abstract]
Weighted-average rates									3.63%	3.58%	3.65%
Louisville Gas And Electric Co [Member] | Ohio Valley Electric Corporation [Member]
Cost Method Investments [Abstract]
Number of electric utilities that are equity owners | Integer									10
Number of companies power is supplied to | Integer									11
Ownership percentage									5.63%
Generation capacity in terms of ownership percentage (in MW) | MW									120
Louisville Gas And Electric Co [Member] | Allowance For Doubtful Accounts [Member]
Allowance for Doubtful Accounts (Details) [Roll Forward]
Balance at beginning of period				2				1	$ 2	$ 1	$ 2
Additions charged to income									2	2	2
Additions charged to other accounts									(1)	1	0
Deductions									2	2	3
Balance at end of period	1				2				1	2	1
Kentucky Utilities Co [Member]
Utility Revenue (Details) [Abstract]
Operating Revenues									$ 1,744	1,749	$ 1,728
Defined Benefits [Abstract]
Percentage in excess of gains and losses equal to the plan's projected benefit obligation to use accelerated amortization									30.00%
Minimum percentage of gains and losses under the accelerated method that are amortized on a straight line basis									10.00%
Maximum percentage of gains and losses under the accelerated that are amortized on a straight line basis									30.00%
Income Taxes [Abstract]
Minimum percentage to be attained of likelihood of uncertain tax position being realized									50.00%
Intercompany tax receivables (payables)	0				(29)				$ 0	(29)
Fuel, Materials and Supplies (Details) [Abstract]
Fuel, materials and supplies on the Balance Sheet	123				154				123	154
Kentucky Utilities Co [Member] | Fuel [Member]
Fuel, Materials and Supplies (Details) [Abstract]
Fuel, materials and supplies on the Balance Sheet	62				98				62	98
Kentucky Utilities Co [Member] | Natural Gas Stored Underground [Member]
Fuel, Materials and Supplies (Details) [Abstract]
Fuel, materials and supplies on the Balance Sheet	0				0				0	0
Kentucky Utilities Co [Member] | Material And Supplies [Member]
Fuel, Materials and Supplies (Details) [Abstract]
Fuel, materials and supplies on the Balance Sheet	61				56				$ 61	$ 56
Kentucky Utilities Co [Member] | Regulated Operations [Member] | Utility Plant [Member]
Depreciation (Details) [Abstract]
Weighted-average rates									3.66%	3.77%	3.71%
Kentucky Utilities Co [Member] | Ohio Valley Electric Corporation [Member]
Cost Method Investments [Abstract]
Number of electric utilities that are equity owners | Integer									10
Number of companies power is supplied to | Integer									11
Ownership percentage									2.50%
Generation capacity in terms of ownership percentage (in MW) | MW									53
Kentucky Utilities Co [Member] | Allowance For Doubtful Accounts [Member]
Allowance for Doubtful Accounts (Details) [Roll Forward]
Balance at beginning of period				$ 2				$ 2	$ 2	$ 2	$ 2
Additions charged to income									4	4	5
Additions charged to other accounts									(1)	0	0
Deductions									4	4	5
Balance at end of period	$ 1				$ 2				$ 1	$ 2	$ 2