Income Taxes (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended				12 Months Ended
	Mar. 31, 2012 Integer		Mar. 31, 2011		Dec. 31, 2011	Dec. 31, 2010
Reconciliation of Income Tax Expense
Federal income tax on Income (Loss) from Continuing Operations Before Income Taxes at statutory tax rate - 35%	$ 281		$ 219
Federal statutory rate	35.00%		35.00%
Increase (decrease) due to:
State income taxes, net of federal income tax benefit	24		25
State valuation allowance adjustments	0		11	[1]
Impact of lower U.K. income tax rates	(21)		(8)
U.S. income tax on foreign earnings - net of foreign tax credit	2		(6)	[2]
Foreign tax reserve adjustments	3		0
Federal income tax credits	(4)		(5)
Amortization of investment tax credit	(2)		(3)
Depreciation not normalized	(2)	[1]	(4)	[1]
State deferred tax rate change	(11)	[3]	0
Net operating loss carryforward adjustment	(6)	[4]	0
Other	(5)		(6)
Total increase (decrease)	(22)		4
Total income tax from continuing operations	259		223
Bonus depreciation percentage	100.00%
Minimum property value for extended deadline for bonus depreciation	1
Minimum production period extended deadline for bonus depreciation (in years)	1
Minimum tax life for extended deadline for bonus depreciation (in years)	10
Tax benefit recorded due to U.K. pension contributions			7
Unrecognized Tax Benefits (Details) [Roll Forward]
Beginning of period	145		251		251
Additions based on tax positions of prior years	4		0
Reductions based on tax positions of prior years	(27)		0
Additions based on tax positions related to the current year	1		0
Reductions based on tax positions related to the current year	0		(1)
Lapse of applicable statutes of limitations	(2)		(2)
Effects of foreign currency translation	0		3
End of period	121		251		145	251
Unrecognized Tax Benefits - Probable Increase (Decrease) Next 12 Months (Details) [Abstract]
Total amount unrecognized tax benefits may increase in next 12 months	17
Total amount unrecognized tax benefits may decrease in next 12 months	111
Total unrecognized tax benefits and related effects that, if recognized, would decrease the effective tax rate	41		181
Unrecognized Tax Benefits - Tax Litigation (Numeric) [Abstract]
Benefit from favorable U.S. Tax Court decision on deductibility of U.K. windfall profit tax						42
Expense from reversal by U.S. Court of Appeals for the Third Circuit on deductibility of U.K. windfall profit tax					$ 39

[1] In February 2011, the Pennsylvania Department of Revenue issued interpretive guidance on the treatment of bonus depreciation for Pennsylvania income tax purposes. In accordance with Corporation Tax Bulletin 2011-01, Pennsylvania allows 100% bonus depreciation for qualifying assets in the same year bonus depreciation is allowed for federal tax purposes. Due to the decrease in projected taxable income related to bonus depreciation, PPL recorded state deferred income tax expense during the three months ended March 31, 2011 related to valuation allowances. Additionally, the 100% Pennsylvania bonus depreciation deduction created a current state income tax benefit for the flow-through impact of Pennsylvania regulated state tax depreciation. The federal provision for 100% bonus depreciation generally applies to property placed in service before January 1, 2012. The placed in service deadline is extended to January 1, 2013 for property that exceeds $1 million, has a production period longer than one year and has a tax life of at least ten years.

[2] During the three months ended March 31, 2011, PPL recorded a $7 million federal income tax benefit related to U.K. pension contributions.

[3] During the three months ended March 31, 2012, PPL recorded an $11 million adjustment related to state deferred tax liabilities.

[4] During the three months ended March 31, 2012, PPL recorded an adjustment to deferred taxes related to net operating loss carryforwards of LKE.