Defined Benefits (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011	Dec. 31, 2011
Pension Benefits - U.S. [Member]
Net Periodic Defined Benefit Costs (Credits) [Line Items]
Service cost	$ 26	$ 23	$ 52	$ 47
Interest cost	54	54	110	109
Expected return on plan assets	(64)	(61)	(130)	(123)
Amortization of:
Prior service cost	6	6	12	12
Actuarial (gain) loss	11	8	21	14
Net periodic defined benefit costs (credits) prior to termination benefits	33	30	65	59
Termination benefits	0	0	0	0
Net periodic defined benefit costs (credits)	33	30	65	59
Pension Benefits - U.K. [Member]
Net Periodic Defined Benefit Costs (Credits) [Line Items]
Service cost	14	12	27	17
Interest cost	85	73	169	112
Expected return on plan assets	(114)	(88)	(225)	(140)
Amortization of:
Prior service cost	1	1	2	2
Actuarial (gain) loss	20	15	40	29
Net periodic defined benefit costs (credits) prior to termination benefits	6	13	13	20
Termination benefits	0	2	0	2
Net periodic defined benefit costs (credits)	6	15	13	22
Expected contribution to pension plans	323		323		161
Employer contributions			275
Other Postretirement Benefits - U.S. [Member]
Net Periodic Defined Benefit Costs (Credits) [Line Items]
Service cost	3	3	6	6
Interest cost	8	8	16	16
Expected return on plan assets	(5)	(5)	(11)	(11)
Amortization of:
Transition obligation	0	1	1	1
Actuarial (gain) loss	1	1	2	3
Net periodic defined benefit costs (credits)	7	8	14	15
PPL Energy Supply LLC [Member]
Amortization of:
Allocated costs of defined benefit plans	9	8	19	15
PPL Energy Supply LLC [Member] | Pension Benefits - U.S. [Member]
Net Periodic Defined Benefit Costs (Credits) [Line Items]
Service cost	2	1	3	2
Interest cost	2	2	4	4
Expected return on plan assets	(3)	(2)	(5)	(4)
Amortization of:
Actuarial (gain) loss	0	1	1	1
Net periodic defined benefit costs (credits)	1	2	3	3
PPL Electric Utilities Corp [Member]
Amortization of:
Allocated costs of defined benefit plans	7	6	15	12
LG And E And KU Energy LLC [Member] | Pension Benefits - U.S. [Member]
Net Periodic Defined Benefit Costs (Credits) [Line Items]
Service cost	5	6	11	12
Interest cost	15	17	32	34
Expected return on plan assets	(17)	(16)	(35)	(32)
Amortization of:
Prior service cost	1	1	2	2
Actuarial (gain) loss	6	6	11	11
Net periodic defined benefit costs (credits)	10	14	21	27
LG And E And KU Energy LLC [Member] | Other Postretirement Benefits - U.S. [Member]
Net Periodic Defined Benefit Costs (Credits) [Line Items]
Service cost	1	1	2	2
Interest cost	2	2	4	5
Expected return on plan assets	(1)	(1)	(2)	(2)
Amortization of:
Transition obligation	1	1	1	1
Prior service cost	1	0	2	1
Actuarial (gain) loss	(1)	0	(1)	0
Net periodic defined benefit costs (credits) prior to termination benefits	3	3	6	7
Louisville Gas And Electric Co [Member]
Amortization of:
Allocated costs of defined benefit plans	3	4	6	8
Louisville Gas And Electric Co [Member] | Pension Benefits - U.S. [Member]
Net Periodic Defined Benefit Costs (Credits) [Line Items]
Service cost	1	1	1	1
Interest cost	3	3	7	7
Expected return on plan assets	(4)	(5)	(9)	(9)
Amortization of:
Prior service cost	0	1	1	1
Actuarial (gain) loss	2	3	5	6
Net periodic defined benefit costs (credits)	2	3	5	6
Kentucky Utilities Co [Member]
Amortization of:
Allocated costs of defined benefit plans	$ 5	$ 5	$ 9	$ 11