Accumulated Other Comprehensive Income (Loss) (Income (Expense) Effect of Reclassifications) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended																12 Months Ended
	Dec. 31, 2014		Sep. 30, 2014		Jun. 30, 2014		Mar. 31, 2014		Dec. 31, 2013		Sep. 30, 2013		Jun. 30, 2013		Mar. 31, 2013		Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Affected Line Item on the Statements of Income [Line Items]
Interest Expense																	$ (1,024)		$ (994)		$ (951)
Other Income (Expense) - net																	118		(23)		(39)
Total Pre-tax																	2,364		1,260		2,009
Income Taxes																	(781)		(163)		(518)
Total After-Tax	551	[1]	490	[1]	218	[1]	324	[1]	(102)	[1],[2]	404	[1]	390	[1]	405	[1]	1,583		1,097		1,491
Amounts Reclassified From Accumulated Other Comprehensive Income [Member]
Affected Line Item on the Statements of Income [Line Items]
Total After-Tax																	(45)		(52)
Available For Sale Securities [Member] | Amounts Reclassified From Accumulated Other Comprehensive Income [Member]
Affected Line Item on the Statements of Income [Line Items]
Other Income (Expense) - net																	13		10
Total Pre-tax																	13		10
Income Taxes																	(7)		(4)
Total After-Tax																	6		6
Qualifying Derivatives [Member] | Amounts Reclassified From Accumulated Other Comprehensive Income [Member]
Affected Line Item on the Statements of Income [Line Items]
Total Pre-tax																	87		163
Income Taxes																	(23)		(80)
Total After-Tax																	64		83
Qualifying Derivatives [Member] | Interest Rate Swaps [Member] | Amounts Reclassified From Accumulated Other Comprehensive Income [Member]
Affected Line Item on the Statements of Income [Line Items]
Interest Expense																	(16)		(20)
Qualifying Derivatives [Member] | Cross Currency Swaps [Member] | Amounts Reclassified From Accumulated Other Comprehensive Income [Member]
Affected Line Item on the Statements of Income [Line Items]
Interest Expense																	4		1
Other Income (Expense) - net																	57		(28)
Qualifying Derivatives [Member] | Energy Commodities [Member] | Amounts Reclassified From Accumulated Other Comprehensive Income [Member]
Affected Line Item on the Statements of Income [Line Items]
Unregulated wholesale energy																	1		240
Energy purchases																	31		(58)
Discontinued operations																	8		23
Other																	2		5
Defined Benefit Plans [Member] | Amounts Reclassified From Accumulated Other Comprehensive Income [Member]
Affected Line Item on the Statements of Income [Line Items]
Total Pre-tax																	(152)		(194)
Income Taxes																	37		53
Total After-Tax																	(115)		(141)
Defined Benefit Plans [Member] | Prior Service Costs [Member] | Amounts Reclassified From Accumulated Other Comprehensive Income [Member]
Affected Line Item on the Statements of Income [Line Items]
Total Pre-tax																	(7)		(10)
Defined Benefit Plans [Member] | Net Actuarial Loss [Member] | Amounts Reclassified From Accumulated Other Comprehensive Income [Member]
Affected Line Item on the Statements of Income [Line Items]
Total Pre-tax																	(145)		(184)
PPL Energy Supply LLC [Member]
Affected Line Item on the Statements of Income [Line Items]
Interest Expense																	(124)		(159)		(158)
Other Income (Expense) - net																	30		32		19
Total Pre-tax																	303		(420)		665
Income Taxes																	(116)	[3]	159	[3]	(236)	[3]
Total After-Tax																	187		(261)		429
PPL Energy Supply LLC [Member] | Amounts Reclassified From Accumulated Other Comprehensive Income [Member]
Affected Line Item on the Statements of Income [Line Items]
Total After-Tax																	23		111
PPL Energy Supply LLC [Member] | Available For Sale Securities [Member] | Amounts Reclassified From Accumulated Other Comprehensive Income [Member]
Affected Line Item on the Statements of Income [Line Items]
Other Income (Expense) - net																	13		10
Total Pre-tax																	13		10
Income Taxes																	(7)		(4)
Total After-Tax																	6		6
PPL Energy Supply LLC [Member] | Qualifying Derivatives [Member] | Amounts Reclassified From Accumulated Other Comprehensive Income [Member]
Affected Line Item on the Statements of Income [Line Items]
Total Pre-tax																	42		207
Income Taxes																	(17)		(84)
Total After-Tax																	25		123
PPL Energy Supply LLC [Member] | Qualifying Derivatives [Member] | Energy Commodities [Member] | Amounts Reclassified From Accumulated Other Comprehensive Income [Member]
Affected Line Item on the Statements of Income [Line Items]
Unregulated wholesale energy																	1		240
Energy purchases																	31		(58)
Discontinued operations																	8		23
Other																	2		2
PPL Energy Supply LLC [Member] | Defined Benefit Plans [Member] | Amounts Reclassified From Accumulated Other Comprehensive Income [Member]
Affected Line Item on the Statements of Income [Line Items]
Total Pre-tax																	(13)		(31)
Income Taxes																	5		13
Total After-Tax																	(8)		(18)
PPL Energy Supply LLC [Member] | Defined Benefit Plans [Member] | Prior Service Costs [Member] | Amounts Reclassified From Accumulated Other Comprehensive Income [Member]
Affected Line Item on the Statements of Income [Line Items]
Total Pre-tax																	(4)		(7)
PPL Energy Supply LLC [Member] | Defined Benefit Plans [Member] | Net Actuarial Loss [Member] | Amounts Reclassified From Accumulated Other Comprehensive Income [Member]
Affected Line Item on the Statements of Income [Line Items]
Total Pre-tax																	(9)		(24)
Kentucky Utilities Co [Member]
Affected Line Item on the Statements of Income [Line Items]
Energy purchases																	(23)		(22)		(32)
Interest Expense																	(77)		(70)		(69)
Other Income (Expense) - net																	(1)		(3)		(8)
Total Pre-tax																	355		360		215
Income Taxes																	$ (135)	[4]	$ (132)	[4]	$ (78)	[4]

[1] Quarterly results can vary depending on, among other things, weather and the forward pricing of power. Accordingly, comparisons among quarters of a year may not be indicative of overall trends and changes in operations.

[2] Fourth quarter of 2013 includes a charge for the termination of the lease of the Colstrip coal-fired electric generating facility in Montana. See Note 8 to the Financial Statements for additional information.

[3] Excludes current and deferred federal and state tax expense recorded to Discontinued Operations of $109 million, $17 million and $27 million in 2014, 2013 and 2012. Also excludes federal and state tax expense (benefit) recorded to OCI of $(56) million, $47 million and $(267) million in 2014, 2013 and 2012.

[4] Excludes deferred federal and state tax expense (benefit) recorded to OCI of less than$(1) million in both 2014 and in 2013 and $1 million in 2012.