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, 2018	Dec. 31, 2017	Dec. 31, 2016
Pension Plan [Member] | U.S. [Member]
Net Periodic Defined Benefit Costs (Credits): [ Abstract]
Service cost	$ 62	$ 65	$ 66
Interest cost	156	168	174
Expected return on plan assets	(249)	(231)	(228)
Amortization of:
Prior service cost (credit)	10	10	8
Actuarial (gain) loss	84	69	50
Net periodic defined benefit costs (credits) prior to settlements and termination benefits	63	81	70
Settlements	0	1	3
Termination benefits	0	1	0
Net periodic defined benefit costs (credits)	63	83	73
Other Changes in Plan Assets and Benefit Obligations Recognized in OCI and Regulatory Assets/Liabilities - Gross: [Abstract]
Settlement	0	(1)	(3)
Net (gain) loss	157	27	253
Prior service costs (credit)	1	(1)	15
Amortization of: [Abstract]
Prior service (cost) credit	(10)	(10)	(8)
Actuarial gain (loss)	(84)	(69)	(50)
Total recognized in OCI and regulatory assets/liabilities	64	(54)	207
Total recognized in net periodic benefit costs, OCI and regulatory assets/liabilities	127	29	280
Other Changes in Plan Assets and Benefit Obligations Recognized in OCI and Regulatory Assets/Liabilities - Gross (Details) [Abstract]
OCI	90	(53)	236
Regulatory assets/liabilities	(26)	(1)	(29)
Total recognized in OCI and regulatory assets/liabilities	64	(54)	207
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	59	53
Pension Plan [Member] | U.K. [Member]
Net Periodic Defined Benefit Costs (Credits): [ Abstract]
Service cost	82	76	69
Interest cost	185	178	235
Expected return on plan assets	(587)	(514)	(504)
Amortization of:
Prior service cost (credit)	0	0	0
Actuarial (gain) loss	151	144	138
Net periodic defined benefit costs (credits) prior to settlements and termination benefits	(169)	(116)	(62)
Settlements	0	0	0
Termination benefits	0	0	0
Net periodic defined benefit costs (credits)	(169)	(116)	(62)
Other Changes in Plan Assets and Benefit Obligations Recognized in OCI and Regulatory Assets/Liabilities - Gross: [Abstract]
Settlement	0	0	0
Net (gain) loss	201	346	7
Prior service costs (credit)	13	0	0
Amortization of: [Abstract]
Prior service (cost) credit	0	0	0
Actuarial gain (loss)	(151)	(144)	(138)
Total recognized in OCI and regulatory assets/liabilities	63	202	(131)
Total recognized in net periodic benefit costs, OCI and regulatory assets/liabilities	(106)	86	(193)
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	63	202	(131)
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	(226)	(151)	(95)
Other Postretirement Benefits Plan [Member]
Net Periodic Defined Benefit Costs (Credits): [ Abstract]
Service cost	7	7	7
Interest cost	21	23	26
Expected return on plan assets	(23)	(22)	(22)
Amortization of:
Prior service cost (credit)	(1)	(1)	0
Actuarial (gain) loss	0	1	1
Net periodic defined benefit costs (credits) prior to settlements and termination benefits	4	8	12
Settlements	0	0	0
Termination benefits	0	0	0
Net periodic defined benefit costs (credits)	4	8	12
Other Changes in Plan Assets and Benefit Obligations Recognized in OCI and Regulatory Assets/Liabilities - Gross: [Abstract]
Settlement	0	0	0
Net (gain) loss	8	(28)	9
Prior service costs (credit)	0	8	0
Amortization of: [Abstract]
Prior service (cost) credit	1	1	(1)
Actuarial gain (loss)	0	(1)	(1)
Total recognized in OCI and regulatory assets/liabilities	9	(20)	7
Total recognized in net periodic benefit costs, OCI and regulatory assets/liabilities	13	(12)	19
Other Changes in Plan Assets and Benefit Obligations Recognized in OCI and Regulatory Assets/Liabilities - Gross (Details) [Abstract]
OCI	20	(25)	7
Regulatory assets/liabilities	(11)	5	0
Total recognized in OCI and regulatory assets/liabilities	9	(20)	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	5	7
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	12	10
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	(1)	0	1
LG And E And KU Energy LLC [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	11	11	6
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	11	11	6
LG And E And KU Energy LLC [Member] | Pension Plan [Member] | U.S. [Member]
Net Periodic Defined Benefit Costs (Credits): [ Abstract]
Service cost	25	24	23
Interest cost	63	68	71
Expected return on plan assets	(102)	(92)	(91)
Amortization of:
Prior service cost (credit)	9	8	8
Actuarial (gain) loss	35	31	21
Net periodic defined benefit costs (credits)	$ 30	$ 39	$ 32
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	$ 40	$ 30	$ 119
Prior service costs (credit)	0	7	0
Amortization of: [Abstract]
Prior service (cost) credit	(9)	(8)	(8)
Actuarial gain (loss)	(35)	(32)	(21)
Total recognized in OCI and regulatory assets/liabilities	(4)	(3)	90
Total recognized in net periodic benefit costs, OCI and regulatory assets/liabilities	26	36	122
Other Changes in Plan Assets and Benefit Obligations Recognized in OCI and Regulatory Assets/Liabilities - Gross (Details) [Abstract]
OCI	(25)	33	42
Regulatory assets/liabilities	21	(36)	48
Total recognized in OCI and regulatory assets/liabilities	(4)	(3)	90
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	$ 21	$ 28	$ 24
Amortization period for the deferred recovery of a regulatory asset	15 years	15 years	15 years
LG And E And KU Energy LLC [Member] | Pension Plan [Member] | U.S. [Member] | Qualified Plan [Member]
Amortization of:
Settlements	$ 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	$ 5
Interest cost	8	9	9
Expected return on plan assets	(9)	(7)	(6)
Amortization of:
Prior service cost (credit)	1	1	3
Actuarial (gain) loss	0	0	(1)
Net periodic defined benefit costs (credits)	$ 4	$ 7	$ 10
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	$ 1	$ (14)	$ 6
Prior service costs (credit)	0	8	0
Amortization of: [Abstract]
Prior service (cost) credit	(1)	(1)	(3)
Actuarial gain (loss)	0	0	1
Total recognized in OCI and regulatory assets/liabilities	0	(7)	4
Total recognized in net periodic benefit costs, OCI and regulatory assets/liabilities	4	0	14
Other Changes in Plan Assets and Benefit Obligations Recognized in OCI and Regulatory Assets/Liabilities - Gross (Details) [Abstract]
OCI	4	(2)	2
Regulatory assets/liabilities	(4)	(5)	2
Total recognized in OCI and regulatory assets/liabilities	0	(7)	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	$ 3	$ 5	$ 6
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	$ (3)	$ (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]
Deferred recovery of the difference between pension costs calculated with pension accounting policy and pension cost using 15 year amortization period	(3)	(4)	(3)
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	(2)	(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	(2)	(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	2	7	5
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	7	5
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	12	13	15
Expected return on plan assets	(22)	(22)	(21)
Amortization of:
Prior service cost (credit)	5	5	4
Actuarial (gain) loss	7	9	7
Net periodic defined benefit costs (credits)	$ 3	$ 6	$ 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	$ (3)	$ (4)	$ (3)
Other Changes in Plan Assets and Benefit Obligations Recognized in OCI and Regulatory Assets/Liabilities - Gross: [Abstract]
Net (gain) loss	22	(9)	22
Prior service costs (credit)	0	7	0
Amortization of: [Abstract]
Prior service (cost) credit	(5)	(5)	(4)
Actuarial gain (loss)	(7)	(9)	(7)
Total recognized in OCI and regulatory assets/liabilities	10	(16)	11
Total recognized in net periodic benefit costs, OCI and regulatory assets/liabilities	13	(10)	17
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	10	(16)	11
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	$ 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	$ (3)	$ (4)	$ (3)
Louisville Gas And Electric Co [Member] | Pension Plan [Member] | U.S. [Member] | Qualified Plan [Member]
Amortization of:
Settlements	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	$ 2	$ 5	$ 4
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)	$ (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	$ 2	$ 3	$ 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)	$ (4)	$ (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	$ 3	$ 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	$ (2)	$ (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	$ 2	$ 4	$ 5
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)	$ (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	$ (2)	$ (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	$ 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	$ (2)	$ (2)	$ (2)