Segment and Related Information (Income Statement and Balance Sheet Data) (Details) $ in Millions		3 Months Ended								12 Months Ended
		Dec. 31, 2017 USD ($)	Sep. 30, 2017 USD ($)	Jun. 30, 2017 USD ($)	Mar. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Sep. 30, 2016 USD ($)	Jun. 30, 2016 USD ($)	Mar. 31, 2016 USD ($)	Dec. 31, 2017 USD ($) Integer		Dec. 31, 2016 USD ($)		Dec. 31, 2015 USD ($)
Income Statement Data
Operating Revenues from external customers		$ 1,926	$ 1,845	$ 1,725	$ 1,951	$ 1,832	$ 1,889	$ 1,785	$ 2,011	$ 7,447		$ 7,517		$ 7,669
Depreciation										1,008		926		883
Amortization										97		80		59
Unrealized (gains) losses on derivatives and other hedging activities										178		19		(77)
Interest Expense										901		888		871
Income from Continuing Operations Before Income Taxes										1,912		2,550		2,068
Income Taxes										784		648		465
Deferred income taxes and investment tax credits										707		560		428
Net income		78	355	292	403	465	473	483	481	1,128		1,902		682
Loss from Discontinued Operations (net of income taxes)										0		0		(921)
Cash Flow Data
Expenditures for long-lived assets										3,171		2,957		3,570
Balance Sheet Data
Total Assets		41,479				38,315				$ 41,479		38,315
Segment Information (Numeric) [Abstract]
Number of reportable segments | Integer										3
PPL Energy Supply Spinoff [Member]
Income Statement Data
Loss from Discontinued Operations (net of income taxes)														(921)
Gain (loss) on disposal group														(879)
U.K. Regulated [Member]
Income Statement Data
Operating Revenues from external customers										$ 2,091		2,207		2,410
Depreciation										230		233		242
Amortization										34		16		6
Unrealized (gains) losses on derivatives and other hedging activities										166		13		(88)
Interest Expense										397		402		417
Income from Continuing Operations Before Income Taxes										804		1,479		1,249
Income Taxes										152		233		128
Deferred income taxes and investment tax credits										66		31		45
Net income										652		1,246		1,121
Cash Flow Data
Expenditures for long-lived assets										1,015		1,031		1,242
Balance Sheet Data
Total Assets		16,813				14,537				16,813		14,537
Segment Information (Numeric) [Abstract]
Net property, plant and equipment not subject to accounting for the effects of certain types of regulation		12,500				10,800				12,500		10,800
Kentucky Regulated [Member]
Income Statement Data
Operating Revenues from external customers										3,156		3,141		3,115
Depreciation										439		404		382
Amortization										24		29		27
Unrealized (gains) losses on derivatives and other hedging activities										6		6		11
Interest Expense										261		260		232
Income from Continuing Operations Before Income Taxes										645		640		547
Income Taxes										359		242		221
Deferred income taxes and investment tax credits										294		291		236
Net income										286		398		326
Cash Flow Data
Expenditures for long-lived assets										892		791		1,210
Balance Sheet Data
Total Assets		14,468				14,037				14,468		14,037
Pennsylvania Regulated [Member]
Income Statement Data
Operating Revenues from external customers										2,195		2,156		2,124
Depreciation										309		253		214
Amortization										33		32		26
Interest Expense										142		129		130
Income from Continuing Operations Before Income Taxes										575		550		416
Income Taxes										216		212		164
Deferred income taxes and investment tax credits										257		221		220
Net income										359		338		252
Cash Flow Data
Expenditures for long-lived assets										1,254		1,134		1,107
Balance Sheet Data
Total Assets		10,082				9,426				10,082		9,426
Corporate And Other [Member]
Income Statement Data
Operating Revenues from external customers										5		13		20
Depreciation										30		36		45
Amortization										6		3		0
Unrealized (gains) losses on derivatives and other hedging activities										6		0		0
Interest Expense										101		97		92
Income from Continuing Operations Before Income Taxes										(112)		(119)		(144)
Income Taxes										57		(39)		(48)
Deferred income taxes and investment tax credits										90		17		(73)
Net income										(169)		(80)		(96)
Cash Flow Data
Expenditures for long-lived assets										10		1		11
Balance Sheet Data
Total Assets		116				315				116		315
Discontinued Operations [Member]
Income Statement Data
Loss from Discontinued Operations (net of income taxes)										0		0		(921)
PPL Electric Utilities Corp [Member]
Income Statement Data
Operating Revenues from external customers		575	547	500	573	537	539	495	585	2,195		2,156		2,124
Depreciation										309		253		214
Amortization										33		32		26
Interest Expense										142		129		130
Income from Continuing Operations Before Income Taxes										575		552		416
Income Taxes										213		212		164
Deferred income taxes and investment tax credits										258		221		220
Net income		111	$ 95	$ 77	$ 79	77	$ 90	$ 79	$ 94	362	[1]	340	[1]	252	[1]
Balance Sheet Data
Total Assets		10,082				9,426				$ 10,082		9,426
Segment Information (Numeric) [Abstract]
Number of operating segments | Integer										2
Number of reportable segments | Integer										1
LG And E And KU Energy LLC [Member]
Income Statement Data
Operating Revenues from external customers										$ 3,156		3,141		3,115
Depreciation										439		404		382
Amortization										24		29		27
Interest Expense										197		197		178
Income from Continuing Operations Before Income Taxes										691		686		603
Income Taxes										375		257		239
Deferred income taxes and investment tax credits										294		291		236
Net income										316		429		364
Balance Sheet Data
Total Assets		14,802				14,371				$ 14,802		14,371
Segment Information (Numeric) [Abstract]
Number of operating segments | Integer										1
Number of reportable segments | Integer										1
Louisville Gas And Electric Co [Member]
Income Statement Data
Operating Revenues from external customers										$ 1,453		1,430		1,444
Depreciation										183		170		162
Amortization										14		14		11
Interest Expense										71		71		57
Income from Continuing Operations Before Income Taxes										344		329		299
Income Taxes										131		126		114
Deferred income taxes and investment tax credits										126		147		126
Net income	[2]									213		203		185
Balance Sheet Data
Total Assets		6,559				6,300				$ 6,559		6,300
Segment Information (Numeric) [Abstract]
Number of operating segments | Integer										1
Number of reportable segments | Integer										1
Kentucky Utilities Co [Member]
Income Statement Data
Operating Revenues from external customers										$ 1,744		1,749		1,728
Depreciation										255		234		220
Amortization										9		14		13
Interest Expense										96		96		82
Income from Continuing Operations Before Income Taxes										418		428		374
Income Taxes										159		163		140
Deferred income taxes and investment tax credits										152		126		160
Net income	[3]									259		265		$ 234
Balance Sheet Data
Total Assets		$ 8,254				$ 8,085				$ 8,254		$ 8,085
Segment Information (Numeric) [Abstract]
Number of operating segments | Integer										1
Number of reportable segments | Integer										1

[1] Net income equals comprehensive income.

[2] Net income equals comprehensive income.

[3] Net income approximates comprehensive income.