Accumulated Other Comprehensive Income (Loss) (After-tax Changes by Component) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period	$ (1,565)	$ (1,940)	$ (788)
Amounts arising during the period	(754)	323
Reclassifications from accumulated other comprehensive income	45	52
Net other comprehensive income during the period	(709)	375	(1,152)
Balance at end of period	(2,274)	(1,565)	(1,940)
Foreign Currency Translation Adjustments [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period	(11)	(149)	(243)
Amounts arising during the period	(275)	138
Reclassifications from accumulated other comprehensive income	0	0
Net other comprehensive income during the period	(275)	138	94
Balance at end of period	(286)	(11)	(149)
Available For Sale Securities Unrealized Gains (Losses) [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period	173	112	90
Amounts arising during the period	35	67
Reclassifications from accumulated other comprehensive income	(6)	(6)
Net other comprehensive income during the period	29	61	22
Balance at end of period	202	173	112
Qualifying Derivatives Unrealized Gains (Losses) [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period	94	132	527
Amounts arising during the period	(10)	45
Reclassifications from accumulated other comprehensive income	(64)	(83)
Net other comprehensive income during the period	(74)	(38)	(395)
Balance at end of period	20	94	132
Equity Investees Accumulated Other Comprehensive Income [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period	1	1	(1)
Amounts arising during the period	0	0
Reclassifications from accumulated other comprehensive income	0	0
Net other comprehensive income during the period	0	0	2
Balance at end of period	1	1	1
Defined Benefit Plans Prior Service Costs [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period	(6)	(14)	(25)
Amounts arising during the period	5	2
Reclassifications from accumulated other comprehensive income	4	6
Net other comprehensive income during the period	9	8	11
Balance at end of period	3	(6)	(14)
Defined Benefit Plans Actuarial Gain (Loss) [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period	(1,817)	(2,023)	(1,137)
Amounts arising during the period	(509)	71
Reclassifications from accumulated other comprehensive income	111	135
Net other comprehensive income during the period	(398)	206	(886)
Balance at end of period	(2,215)	(1,817)	(2,023)
Defined Benefit Plans Transition Assset Obligation [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period	1	1	1
Amounts arising during the period	0	0
Reclassifications from accumulated other comprehensive income	0	0
Net other comprehensive income during the period	0	0	0
Balance at end of period	1	1	1
PPL Energy Supply LLC [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period	77	48	487
Amounts arising during the period	(77)	140
Reclassifications from accumulated other comprehensive income	(23)	(111)
Net other comprehensive income during the period	(100)	29	(439)
Balance at end of period	(23)	77	48
PPL Energy Supply LLC [Member] | Available For Sale Securities Unrealized Gains (Losses) [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period	173	112	90
Amounts arising during the period	35	67
Reclassifications from accumulated other comprehensive income	(6)	(6)
Net other comprehensive income during the period	29	61	22
Balance at end of period	202	173	112
PPL Energy Supply LLC [Member] | Qualifying Derivatives Unrealized Gains (Losses) [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period	88	211	606
Amounts arising during the period	0	0
Reclassifications from accumulated other comprehensive income	(25)	(123)
Net other comprehensive income during the period	(25)	(123)	(395)
Balance at end of period	63	88	211
PPL Energy Supply LLC [Member] | Defined Benefit Plans Prior Service Costs [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period	(4)	(10)	(16)
Amounts arising during the period	8	2
Reclassifications from accumulated other comprehensive income	3	4
Net other comprehensive income during the period	11	6	6
Balance at end of period	7	(4)	(10)
PPL Energy Supply LLC [Member] | Defined Benefit Plans Actuarial Gain (Loss) [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period	(180)	(265)	(193)
Amounts arising during the period	(120)	71
Reclassifications from accumulated other comprehensive income	5	14
Net other comprehensive income during the period	(115)	85	(72)
Balance at end of period	(295)	(180)	(265)
PPL Energy Supply LLC [Member] | Defined Benefit Plans Transition Assset Obligation [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period	0	0	0
Amounts arising during the period	0	0
Reclassifications from accumulated other comprehensive income	0	0
Net other comprehensive income during the period	0	0	0
Balance at end of period	0	0	0
LG And E And KU Energy LLC [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period	13	(15)	4
Amounts arising during the period	(57)	28
Reclassifications from accumulated other comprehensive income	(1)
Net other comprehensive income during the period	(58)	28	(19)
Balance at end of period	(45)	13	(15)
LG And E And KU Energy LLC [Member] | Available For Sale Securities Unrealized Gains (Losses) [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period	0	0	0
Amounts arising during the period	0
Reclassifications from accumulated other comprehensive income	0
Net other comprehensive income during the period	0	0	0
Balance at end of period	0	0	0
LG And E And KU Energy LLC [Member] | Qualifying Derivatives Unrealized Gains (Losses) [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period	0	0	0
Amounts arising during the period	0
Reclassifications from accumulated other comprehensive income	0
Net other comprehensive income during the period	0	0	0
Balance at end of period	0	0	0
LG And E And KU Energy LLC [Member] | Equity Investees Accumulated Other Comprehensive Income [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period	1		0
Reclassifications from accumulated other comprehensive income	(1)
Net other comprehensive income during the period	(1)		1
Balance at end of period	0		1
LG And E And KU Energy LLC [Member] | Defined Benefit Plans Prior Service Costs [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period	(2)	(2)	(2)
Amounts arising during the period	(7)
Reclassifications from accumulated other comprehensive income	1
Net other comprehensive income during the period	(6)	0	(2)
Balance at end of period	(8)	(2)	(2)
LG And E And KU Energy LLC [Member] | Defined Benefit Plans Actuarial Gain (Loss) [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period	14	(14)	6
Amounts arising during the period	(50)	28
Reclassifications from accumulated other comprehensive income	(1)
Net other comprehensive income during the period	(51)	28	(20)
Balance at end of period	(37)	14	(14)
LG And E And KU Energy LLC [Member] | Defined Benefit Plans Transition Assset Obligation [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period	0	0	0
Amounts arising during the period	0
Reclassifications from accumulated other comprehensive income	0
Net other comprehensive income during the period	0	0	0
Balance at end of period	$ 0	$ 0	$ 0