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, 2019	Dec. 31, 2018	Dec. 31, 2017
Pension Plan [Member] | U.S. [Member]
Net Periodic Defined Benefit Costs (Credits): [ Abstract]
Service cost	$ 50	$ 62	$ 65
Interest cost	164	156	168
Expected return on plan assets	(245)	(249)	(231)
Amortization of:
Prior service cost (credit)	8	10	10
Actuarial (gain) loss	56	84	69
Net periodic defined benefit costs (credits) prior to settlements and termination benefits	33	63	81
Settlements	1	0	1
Termination benefits	0	0	1
Net periodic defined benefit costs (credits)	34	63	83
Other Changes in Plan Assets and Benefit Obligations Recognized in OCI and Regulatory Assets/Liabilities - Gross: [Abstract]
Settlement	(1)	0	(1)
Net (gain) loss	(121)	157	27
Prior service costs (credit)	2	1	(1)
Amortization of: [Abstract]
Prior service (cost) credit	(8)	(10)	(10)
Actuarial gain (loss)	(56)	(84)	(69)
Total recognized in OCI and regulatory assets/liabilities	(184)	64	(54)
Total recognized in net periodic benefit costs, OCI and regulatory assets/liabilities	(150)	127	29
Other Changes in Plan Assets and Benefit Obligations Recognized in OCI and Regulatory Assets/Liabilities - Gross (Details) [Abstract]
OCI	(194)	90	(53)
Regulatory assets/liabilities	10	(26)	(1)
Total recognized in OCI and regulatory assets/liabilities	(184)	64	(54)
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	18	40	59
Pension Plan [Member] | U.K. [Member]
Net Periodic Defined Benefit Costs (Credits): [ Abstract]
Service cost	68	82	76
Interest cost	187	185	178
Expected return on plan assets	(588)	(587)	(514)
Amortization of:
Prior service cost (credit)	1	0	0
Actuarial (gain) loss	92	151	144
Net periodic defined benefit costs (credits) prior to settlements and termination benefits	(240)	(169)	(116)
Settlements	0	0	0
Termination benefits	0	0	0
Net periodic defined benefit costs (credits)	(240)	(169)	(116)
Other Changes in Plan Assets and Benefit Obligations Recognized in OCI and Regulatory Assets/Liabilities - Gross: [Abstract]
Settlement	0	0	0
Net (gain) loss	723	201	346
Prior service costs (credit)	0	13	0
Amortization of: [Abstract]
Prior service (cost) credit	(1)	0	0
Actuarial gain (loss)	(92)	(151)	(144)
Total recognized in OCI and regulatory assets/liabilities	630	63	202
Total recognized in net periodic benefit costs, OCI and regulatory assets/liabilities	390	(106)	86
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	630	63	202
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	(287)	(226)	(151)
Other Postretirement Benefits Plan [Member]
Net Periodic Defined Benefit Costs (Credits): [ Abstract]
Service cost	6	7	7
Interest cost	22	21	23
Expected return on plan assets	(18)	(23)	(22)
Amortization of:
Prior service cost (credit)	(1)	(1)	(1)
Actuarial (gain) loss	1	0	1
Net periodic defined benefit costs (credits) prior to settlements and termination benefits	10	4	8
Settlements	0	0	0
Termination benefits	0	0	0
Net periodic defined benefit costs (credits)	10	4	8
Other Changes in Plan Assets and Benefit Obligations Recognized in OCI and Regulatory Assets/Liabilities - Gross: [Abstract]
Settlement	0	0	0
Net (gain) loss	(18)	8	(28)
Prior service costs (credit)	0	0	8
Amortization of: [Abstract]
Prior service (cost) credit	1	1	1
Actuarial gain (loss)	(1)	0	(1)
Total recognized in OCI and regulatory assets/liabilities	(18)	9	(20)
Total recognized in net periodic benefit costs, OCI and regulatory assets/liabilities	(8)	13	(12)
Other Changes in Plan Assets and Benefit Obligations Recognized in OCI and Regulatory Assets/Liabilities - Gross (Details) [Abstract]
OCI	(13)	20	(25)
Regulatory assets/liabilities	(5)	(11)	5
Total recognized in OCI and regulatory assets/liabilities	(18)	9	(20)
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	$ 8	2	5
PPL Electric Utilities Corp [Member]
Amortization of:
Amortization period for the deferred recovery of a regulatory asset	5 years
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]
Amortization period for the deferred recovery of a regulatory asset	5 years
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	$ (4)	4	12
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	4	(1)	0
LG And E And KU Energy LLC [Member] | Pension Plan [Member] | U.S. [Member]
Net Periodic Defined Benefit Costs (Credits): [ Abstract]
Service cost	22	25	24
Interest cost	66	63	68
Expected return on plan assets	(101)	(102)	(92)
Amortization of:
Prior service cost (credit)	8	9	8
Actuarial (gain) loss	22	35	31
Net periodic defined benefit costs (credits)	$ 17	$ 30	$ 39
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	$ 5	$ 11	$ 11
Other Changes in Plan Assets and Benefit Obligations Recognized in OCI and Regulatory Assets/Liabilities - Gross: [Abstract]
Net (gain) loss	(37)	40	30
Prior service costs (credit)	2	0	7
Amortization of: [Abstract]
Prior service (cost) credit	(8)	(9)	(8)
Actuarial gain (loss)	(22)	(35)	(32)
Total recognized in OCI and regulatory assets/liabilities	(65)	(4)	(3)
Total recognized in net periodic benefit costs, OCI and regulatory assets/liabilities	(48)	26	36
Other Changes in Plan Assets and Benefit Obligations Recognized in OCI and Regulatory Assets/Liabilities - Gross (Details) [Abstract]
OCI	13	(25)	33
Regulatory assets/liabilities	(78)	21	(36)
Total recognized in OCI and regulatory assets/liabilities	(65)	(4)	(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	$ 12	$ 21	$ 28
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	$ 5	$ 11	$ 11
LG And E And KU Energy LLC [Member] | Pension Plan [Member] | U.S. [Member] | Qualified Plan [Member]
Amortization of:
Settlements	5	6	5
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	8	8	9
Expected return on plan assets	(8)	(9)	(7)
Amortization of:
Prior service cost (credit)	1	1	1
Actuarial (gain) loss	(1)	0	0
Net periodic defined benefit costs (credits)	$ 4	$ 4	$ 7
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]
Net (gain) loss	$ (14)	$ 1	$ (14)
Prior service costs (credit)	0	0	8
Amortization of: [Abstract]
Prior service (cost) credit	(1)	(1)	(1)
Actuarial gain (loss)	1	0	0
Total recognized in OCI and regulatory assets/liabilities	(14)	0	(7)
Total recognized in net periodic benefit costs, OCI and regulatory assets/liabilities	(10)	4	0
Other Changes in Plan Assets and Benefit Obligations Recognized in OCI and Regulatory Assets/Liabilities - Gross (Details) [Abstract]
OCI	(7)	4	(2)
Regulatory assets/liabilities	(7)	(4)	(5)
Total recognized in OCI and regulatory assets/liabilities	(14)	0	(7)
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	$ 3	$ 5
Amortization period for the deferred recovery of a regulatory asset	15 years	15 years	15 years
LG And E And KU Energy LLC [Member] | LGE [Member] | Other Postretirement Benefits 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	$ (2)	$ (3)	$ (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]
Deferred recovery of the difference between pension costs calculated with pension accounting policy and pension cost using 15 year amortization period	(2)	(3)	(4)
LG And E And KU Energy LLC [Member] | KU [Member] | Other Postretirement Benefits 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	(1)	(2)	(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	(1)	(2)	(2)
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	7
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	7
Louisville Gas And Electric Co [Member] | Pension Plan [Member] | U.S. [Member]
Net Periodic Defined Benefit Costs (Credits): [ Abstract]
Service cost	1	1	1
Interest cost	11	12	13
Expected return on plan assets	(21)	(22)	(22)
Amortization of:
Prior service cost (credit)	5	5	5
Actuarial (gain) loss	9	7	9
Net periodic defined benefit costs (credits)	$ 5	$ 3	$ 6
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	$ (2)	$ (3)	$ (4)
Other Changes in Plan Assets and Benefit Obligations Recognized in OCI and Regulatory Assets/Liabilities - Gross: [Abstract]
Net (gain) loss	(19)	22	(9)
Prior service costs (credit)	0	0	7
Amortization of: [Abstract]
Prior service (cost) credit	(5)	(5)	(5)
Actuarial gain (loss)	(9)	(7)	(9)
Total recognized in OCI and regulatory assets/liabilities	(33)	10	(16)
Total recognized in net periodic benefit costs, OCI and regulatory assets/liabilities	(28)	13	(10)
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	(16)
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	$ 3	$ 4	$ 8
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	$ (2)	$ (3)	$ (4)
Louisville Gas And Electric Co [Member] | Pension Plan [Member] | U.S. [Member] | Qualified Plan [Member]
Amortization of:
Settlements	5	6	5
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	$ 5
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	$ (2)	$ (3)	$ (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	$ 2	$ 2	$ 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	$ (2)	$ (3)	$ (4)
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	$ 3
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)	$ (2)	$ (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)	$ 2	$ 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	$ (1)	$ (2)	$ (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)	$ (2)	$ (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	$ 1	$ 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)	$ (2)	$ (2)