Retirement and Postemployment Benefits (Net Period Defined Benefit Costs (Credits) and Other Changes in Plan Assets and Benefit Obligations) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Pension Plan [Member] | U.S. [Member]
Net Periodic Defined Benefit Costs (Credits): [ Abstract]
Service cost	$ 56	$ 50	$ 62
Interest cost	146	164	156
Expected return on plan assets	(246)	(245)	(249)
Amortization of:
Prior service cost (credit)	9	8	10
Actuarial (gain) loss	89	56	84
Net periodic defined benefit costs (credits) prior to settlements and termination benefits	54	33	63
Settlements	23	1	0
Net Periodic Defined Benefit Costs (Credits)	77	34	63
Other Changes in Plan Assets and Benefit Obligations Recognized in OCI and Regulatory Assets/Liabilities - Gross: [Abstract]
Settlement	(23)	(1)	0
Net (gain) loss	(221)	(121)	157
Prior service costs (credit)	1	2	1
Amortization of: [Abstract]
Prior service (cost) credit	(9)	(8)	(10)
Actuarial gain (loss)	(89)	(56)	(84)
Total recognized in OCI and regulatory assets/liabilities	(341)	(184)	64
Total recognized in net periodic benefit costs, OCI and regulatory assets/liabilities	(264)	(150)	127
Other Changes in Plan Assets and Benefit Obligations Recognized in OCI and Regulatory Assets/Liabilities - Gross (Details) [Abstract]
OCI	(428)	(194)	90
Regulatory assets/liabilities	87	10	(26)
Total recognized in OCI and regulatory assets/liabilities	(341)	(184)	64
Net Periodic Defined Benefit Costs (Credits) Charged to Operating Expense or Regulatory Assets, Excluding Amounts Charged to Construction and Other Non-expense Accounts (Details) [Abstract]
Net periodic defined benefit costs (credits) charged to operating expense or regulatory assets, excluding amounts charged to construction and other non-expense accounts	40	18	40
Pension Plan [Member] | U.K. [Member]
Net Periodic Defined Benefit Costs (Credits): [ Abstract]
Service cost	89	68	82
Interest cost	143	187	185
Expected return on plan assets	(622)	(588)	(587)
Amortization of:
Prior service cost (credit)	1	1	0
Actuarial (gain) loss	213	92	151
Net periodic defined benefit costs (credits) prior to settlements and termination benefits	(176)	(240)	(169)
Settlements	0	0	0
Net Periodic Defined Benefit Costs (Credits)	(176)	(240)	(169)
Other Changes in Plan Assets and Benefit Obligations Recognized in OCI and Regulatory Assets/Liabilities - Gross: [Abstract]
Settlement	0	0	0
Net (gain) loss	459	723	201
Prior service costs (credit)	0	0	13
Amortization of: [Abstract]
Prior service (cost) credit	(1)	(1)	0
Actuarial gain (loss)	(213)	(92)	(151)
Total recognized in OCI and regulatory assets/liabilities	245	630	63
Total recognized in net periodic benefit costs, OCI and regulatory assets/liabilities	69	390	(106)
Other Changes in Plan Assets and Benefit Obligations Recognized in OCI and Regulatory Assets/Liabilities - Gross (Details) [Abstract]
Total recognized in OCI and regulatory assets/liabilities	245	630	63
Net Periodic Defined Benefit Costs (Credits) Charged to Operating Expense or Regulatory Assets, Excluding Amounts Charged to Construction and Other Non-expense Accounts (Details) [Abstract]
Net periodic defined benefit costs (credits) charged to operating expense or regulatory assets, excluding amounts charged to construction and other non-expense accounts	(237)	(287)	(226)
Other Postretirement Benefits Plan [Member]
Net Periodic Defined Benefit Costs (Credits): [ Abstract]
Service cost	6	6	7
Interest cost	19	22	21
Expected return on plan assets	(21)	(18)	(23)
Amortization of:
Prior service cost (credit)	1	(1)	(1)
Actuarial (gain) loss	0	1	0
Net periodic defined benefit costs (credits) prior to settlements and termination benefits	5	10	4
Settlements	0	0	0
Net Periodic Defined Benefit Costs (Credits)	5	10	4
Other Changes in Plan Assets and Benefit Obligations Recognized in OCI and Regulatory Assets/Liabilities - Gross: [Abstract]
Settlement	0	0	0
Net (gain) loss	(6)	(18)	8
Prior service costs (credit)	5	0	0
Amortization of: [Abstract]
Prior service (cost) credit	(1)	1	1
Actuarial gain (loss)	0	(1)	0
Total recognized in OCI and regulatory assets/liabilities	(2)	(18)	9
Total recognized in net periodic benefit costs, OCI and regulatory assets/liabilities	3	(8)	13
Other Changes in Plan Assets and Benefit Obligations Recognized in OCI and Regulatory Assets/Liabilities - Gross (Details) [Abstract]
OCI	(12)	(13)	20
Regulatory assets/liabilities	10	(5)	(11)
Total recognized in OCI and regulatory assets/liabilities	(2)	(18)	9
Net Periodic Defined Benefit Costs (Credits) Charged to Operating Expense or Regulatory Assets, Excluding Amounts Charged to Construction and Other Non-expense Accounts (Details) [Abstract]
Net periodic defined benefit costs (credits) charged to operating expense or regulatory assets, excluding amounts charged to construction and other non-expense accounts	4	8	2
PPL Electric Utilities Corp [Member] | Pension Plan [Member] | U.S. [Member]
Net Periodic Defined Benefit Costs (Credits) Charged to Operating Expense or Regulatory Assets, Excluding Amounts Charged to Construction and Other Non-expense Accounts (Details) [Abstract]
Net periodic defined benefit costs (credits) charged to operating expense or regulatory assets, excluding amounts charged to construction and other non-expense accounts	(2)	(4)	4
PPL Electric Utilities Corp [Member] | Other Postretirement Benefits Plan [Member]
Net Periodic Defined Benefit Costs (Credits) Charged to Operating Expense or Regulatory Assets, Excluding Amounts Charged to Construction and Other Non-expense Accounts (Details) [Abstract]
Net periodic defined benefit costs (credits) charged to operating expense or regulatory assets, excluding amounts charged to construction and other non-expense accounts	2	4	(1)
LG And E And KU Energy LLC [Member] | Pension Plan [Member] | U.S. [Member]
Net Periodic Defined Benefit Costs (Credits): [ Abstract]
Service cost	24	22	25
Interest cost	57	66	63
Expected return on plan assets	(101)	(101)	(102)
Amortization of:
Prior service cost (credit)	8	8	9
Actuarial (gain) loss	41	22	35
Net periodic defined benefit costs (credits) prior to settlements and termination benefits	29	17	30
Settlements	15	0	0
Net Periodic Defined Benefit Costs (Credits)	$ 44	$ 17	$ 30
Amortization period for the deferred recovery of a regulatory asset	15 years	15 years	15 years
Deferred recovery of the difference between pension costs calculated with pension accounting policy and pension cost using 15 year amortization period	$ 11	$ (5)	$ 11
Other Changes in Plan Assets and Benefit Obligations Recognized in OCI and Regulatory Assets/Liabilities - Gross: [Abstract]
Settlement	(15)	0	0
Net (gain) loss	(29)	(37)	40
Prior service costs (credit)	2	2	0
Amortization of: [Abstract]
Prior service (cost) credit	(8)	(8)	(9)
Actuarial gain (loss)	(41)	(22)	(35)
Total recognized in OCI and regulatory assets/liabilities	(91)	(65)	(4)
Total recognized in net periodic benefit costs, OCI and regulatory assets/liabilities	(47)	(48)	26
Other Changes in Plan Assets and Benefit Obligations Recognized in OCI and Regulatory Assets/Liabilities - Gross (Details) [Abstract]
OCI	(5)	13	(25)
Regulatory assets/liabilities	(86)	(78)	21
Total recognized in OCI and regulatory assets/liabilities	(91)	(65)	(4)
Net Periodic Defined Benefit Costs (Credits) Charged to Operating Expense or Regulatory Assets, Excluding Amounts Charged to Construction and Other Non-expense Accounts (Details) [Abstract]
Net periodic defined benefit costs (credits) charged to operating expense or regulatory assets, excluding amounts charged to construction and other non-expense accounts	$ 20	$ 12	$ 21
Amortization period for the deferred recovery of a regulatory asset	15 years	15 years	15 years
Deferred recovery of the difference between pension costs calculated with pension accounting policy and pension cost using 15 year amortization period	$ 11	$ (5)	$ 11
LG And E And KU Energy LLC [Member] | Pension Plan [Member] | U.S. [Member] | Qualified Plan [Member]
Amortization of:
Settlements	15	5	6
LG And E And KU Energy LLC [Member] | Other Postretirement Benefits Plan [Member]
Net Periodic Defined Benefit Costs (Credits): [ Abstract]
Service cost	4	4	4
Interest cost	7	8	8
Expected return on plan assets	(9)	(8)	(9)
Amortization of:
Prior service cost (credit)	1	1	1
Actuarial (gain) loss	(1)	(1)	0
Net periodic defined benefit costs (credits) prior to settlements and termination benefits	$ 2	$ 4	$ 4
Amortization period for the deferred recovery of a regulatory asset	15 years	15 years	15 years
Other Changes in Plan Assets and Benefit Obligations Recognized in OCI and Regulatory Assets/Liabilities - Gross: [Abstract]
Settlement	$ 0	$ 0	$ 0
Net (gain) loss	(1)	(14)	1
Prior service costs (credit)	5	0	0
Amortization of: [Abstract]
Prior service (cost) credit	(1)	(1)	(1)
Actuarial gain (loss)	1	1	0
Total recognized in OCI and regulatory assets/liabilities	4	(14)	0
Total recognized in net periodic benefit costs, OCI and regulatory assets/liabilities	6	(10)	4
Other Changes in Plan Assets and Benefit Obligations Recognized in OCI and Regulatory Assets/Liabilities - Gross (Details) [Abstract]
OCI	(2)	(7)	4
Regulatory assets/liabilities	6	(7)	(4)
Total recognized in OCI and regulatory assets/liabilities	4	(14)	0
Net Periodic Defined Benefit Costs (Credits) Charged to Operating Expense or Regulatory Assets, Excluding Amounts Charged to Construction and Other Non-expense Accounts (Details) [Abstract]
Net periodic defined benefit costs (credits) charged to operating expense or regulatory assets, excluding amounts charged to construction and other non-expense accounts	$ 1	$ 2	$ 3
Amortization period for the deferred recovery of a regulatory asset	15 years	15 years	15 years
LG And E And KU Energy LLC [Member] | Other Postretirement Benefits Plan [Member] | U.S. [Member]
Amortization of:
Settlements	$ 0	$ 0	$ 0
Net Periodic Defined Benefit Costs (Credits)	$ 2	4	4
Louisville Gas And Electric Co [Member] | Pension Plan [Member]
Amortization of:
Deferred recovery of the difference between pension costs calculated with pension accounting policy and pension cost using 15 year amortization period		3	2
Net Periodic Defined Benefit Costs (Credits) Charged to Operating Expense or Regulatory Assets, Excluding Amounts Charged to Construction and Other Non-expense Accounts (Details) [Abstract]
Deferred recovery of the difference between pension costs calculated with pension accounting policy and pension cost using 15 year amortization period		3	2
Louisville Gas And Electric Co [Member] | Pension Plan [Member] | U.S. [Member]
Net Periodic Defined Benefit Costs (Credits): [ Abstract]
Service cost		1	1
Interest cost		11	12
Expected return on plan assets		(21)	(22)
Amortization of:
Prior service cost (credit)		5	5
Actuarial (gain) loss		9	7
Net Periodic Defined Benefit Costs (Credits)		$ 5	$ 3
Amortization period for the deferred recovery of a regulatory asset	15 years	15 years	15 years
Deferred recovery of the difference between pension costs calculated with pension accounting policy and pension cost using 15 year amortization period	$ (3)	$ (2)	$ (3)
Other Changes in Plan Assets and Benefit Obligations Recognized in OCI and Regulatory Assets/Liabilities - Gross: [Abstract]
Net (gain) loss		(19)	22
Prior service costs (credit)		0	0
Amortization of: [Abstract]
Prior service (cost) credit		(5)	(5)
Actuarial gain (loss)		(9)	(7)
Total recognized in OCI and regulatory assets/liabilities		(33)	10
Total recognized in net periodic benefit costs, OCI and regulatory assets/liabilities		(28)	13
Other Changes in Plan Assets and Benefit Obligations Recognized in OCI and Regulatory Assets/Liabilities - Gross (Details) [Abstract]
Total recognized in OCI and regulatory assets/liabilities		(33)	10
Net Periodic Defined Benefit Costs (Credits) Charged to Operating Expense or Regulatory Assets, Excluding Amounts Charged to Construction and Other Non-expense Accounts (Details) [Abstract]
Net periodic defined benefit costs (credits) charged to operating expense or regulatory assets, excluding amounts charged to construction and other non-expense accounts	$ 4	$ 3	$ 4
Amortization period for the deferred recovery of a regulatory asset	15 years	15 years	15 years
Deferred recovery of the difference between pension costs calculated with pension accounting policy and pension cost using 15 year amortization period	$ (3)	$ (2)	$ (3)
Louisville Gas And Electric Co [Member] | Pension Plan [Member] | U.S. [Member] | Qualified Plan [Member]
Amortization of:
Settlements	$ 5	6
Louisville Gas And Electric Co [Member] | Pension Plan [Member] | U.S. [Member] | LKE [Member]
Net Periodic Defined Benefit Costs Allocated to Subsidiary by Sponsor (Numeric) [Abstract]
Costs allocated to subsidiary by plan sponsors		$ 0	$ 2
Louisville Gas And Electric Co [Member] | Other Postretirement Benefits Plan [Member]
Amortization of:
Amortization period for the deferred recovery of a regulatory asset	15 years	15 years	15 years
Deferred recovery of the difference between pension costs calculated with pension accounting policy and pension cost using 15 year amortization period	$ (3)	$ (2)	$ (3)
Net Periodic Defined Benefit Costs (Credits) Charged to Operating Expense or Regulatory Assets, Excluding Amounts Charged to Construction and Other Non-expense Accounts (Details) [Abstract]
Net periodic defined benefit costs (credits) charged to operating expense or regulatory assets, excluding amounts charged to construction and other non-expense accounts	$ 2	$ 2	$ 2
Amortization period for the deferred recovery of a regulatory asset	15 years	15 years	15 years
Deferred recovery of the difference between pension costs calculated with pension accounting policy and pension cost using 15 year amortization period	$ (3)	$ (2)	$ (3)
Louisville Gas And Electric Co [Member] | Other Postretirement Benefits Plan [Member] | LKE [Member]
Net Periodic Defined Benefit Costs Allocated to Subsidiary by Sponsor (Numeric) [Abstract]
Costs allocated to subsidiary by plan sponsors		$ 2	$ 2
Kentucky Utilities Co [Member] | Pension Plan [Member] | U.S. [Member]
Amortization of:
Amortization period for the deferred recovery of a regulatory asset	15 years	15 years	15 years
Deferred recovery of the difference between pension costs calculated with pension accounting policy and pension cost using 15 year amortization period	$ (1)	$ (1)	$ (2)
Net Periodic Defined Benefit Costs (Credits) Charged to Operating Expense or Regulatory Assets, Excluding Amounts Charged to Construction and Other Non-expense Accounts (Details) [Abstract]
Net periodic defined benefit costs (credits) charged to operating expense or regulatory assets, excluding amounts charged to construction and other non-expense accounts	$ 1	$ (1)	$ 2
Amortization period for the deferred recovery of a regulatory asset	15 years	15 years	15 years
Deferred recovery of the difference between pension costs calculated with pension accounting policy and pension cost using 15 year amortization period	$ (1)	$ (1)	$ (2)
Kentucky Utilities Co [Member] | Other Postretirement Benefits Plan [Member]
Amortization of:
Amortization period for the deferred recovery of a regulatory asset	15 years	15 years	15 years
Deferred recovery of the difference between pension costs calculated with pension accounting policy and pension cost using 15 year amortization period	$ (1)	$ (1)	$ (2)
Net Periodic Defined Benefit Costs (Credits) Charged to Operating Expense or Regulatory Assets, Excluding Amounts Charged to Construction and Other Non-expense Accounts (Details) [Abstract]
Net periodic defined benefit costs (credits) charged to operating expense or regulatory assets, excluding amounts charged to construction and other non-expense accounts	$ 0	$ 0	$ 1
Amortization period for the deferred recovery of a regulatory asset	15 years	15 years	15 years
Deferred recovery of the difference between pension costs calculated with pension accounting policy and pension cost using 15 year amortization period	$ (1)	$ (1)	$ (2)