Defined Benefits (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Pension Benefits - U.S. [Member]
Net Periodic Defined Benefit Costs (Credits) [Line Items]
Service cost	$ 31	$ 26
Interest cost	54	56
Expected return on plan assets	(74)	(66)
Amortization of:
Prior service cost	6	6
Actuarial (gain) loss	20	10
Net periodic defined benefit costs (credits)	37	32
Pension Benefits - U.K. [Member]
Net Periodic Defined Benefit Costs (Credits) [Line Items]
Service cost	18	13
Interest cost	81	84
Expected return on plan assets	(118)	(111)
Amortization of:
Prior service cost		1
Actuarial (gain) loss	38	20
Net periodic defined benefit costs (credits)	19	7
Other Postretirement Benefits - U.S. [Member]
Net Periodic Defined Benefit Costs (Credits) [Line Items]
Service cost	4	3
Interest cost	7	8
Expected return on plan assets	(6)	(6)
Amortization of:
Transition obligation		1
Actuarial (gain) loss	1	1
Net periodic defined benefit costs (credits)	6	7
PPL Energy Supply LLC [Member] | PPL Services [Member]
Net Periodic Defined Benefit Costs Allocated to Subsidiary by Sponsor (Numeric) [Abstract]
Costs allocated to subsidiary by plan sponsors	11	10
PPL Energy Supply LLC [Member] | Pension Benefits - U.S. [Member]
Net Periodic Defined Benefit Costs (Credits) [Line Items]
Service cost	2	1
Interest cost	2	2
Expected return on plan assets	(3)	(2)
Amortization of:
Actuarial (gain) loss	1	1
Net periodic defined benefit costs (credits)	2	2
PPL Electric Utilities Corp [Member] | PPL Services [Member]
Net Periodic Defined Benefit Costs Allocated to Subsidiary by Sponsor (Numeric) [Abstract]
Costs allocated to subsidiary by plan sponsors	9	8
LG And E And KU Energy LLC [Member] | Pension Benefits - U.S. [Member]
Net Periodic Defined Benefit Costs (Credits) [Line Items]
Service cost	7	6
Interest cost	16	17
Expected return on plan assets	(21)	(18)
Amortization of:
Prior service cost	1	1
Actuarial (gain) loss	8	5
Net periodic defined benefit costs (credits)	11	11
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
Interest cost	2	2
Expected return on plan assets	(1)	(1)
Amortization of:
Prior service cost	1	1
Net periodic defined benefit costs (credits)	3	3
Louisville Gas And Electric Co [Member] | LKE [Member]
Net Periodic Defined Benefit Costs Allocated to Subsidiary by Sponsor (Numeric) [Abstract]
Costs allocated to subsidiary by plan sponsors	3	3
Louisville Gas And Electric Co [Member] | Pension Benefits - U.S. [Member]
Net Periodic Defined Benefit Costs (Credits) [Line Items]
Service cost	1
Interest cost	3	4
Expected return on plan assets	(5)	(5)
Amortization of:
Prior service cost	1	1
Actuarial (gain) loss	3	3
Net periodic defined benefit costs (credits)	3	3
Kentucky Utilities Co [Member] | LKE [Member]
Net Periodic Defined Benefit Costs Allocated to Subsidiary by Sponsor (Numeric) [Abstract]
Costs allocated to subsidiary by plan sponsors	$ 4	$ 4