Commitments and Contingencies - Legal Matters and Regulatory Issues (Details) $ in Millions	1 Months Ended
	Jun. 30, 2017 mi	Jul. 31, 2014 claim	Dec. 31, 2013 resident	Mar. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)	Jun. 01, 2015
Claim By Former Affiliate [Abstract]
Percent of ownership of Talen Energy by Riverstone						35.00%
PPL Electric [Member] | PPL Electric Additional Sites [Member]
Claim By Former Affiliate [Abstract]
Accrual for Environmental Loss Contingencies | $				$ 10	$ 10
LGE [Member]
Legal Matters - Cane Run Environmental Claims (Numeric) [Abstract]
Number of residents that filed class action suit | resident			6
Number of remaining unresolved Clean Air Act violation claims after July 2014 court ruling | claim		1
LGE [Member] | Minimum [Member]
Legal Matters - Cane Run Environmental Claims (Numeric) [Abstract]
Number of miles within plant that would include a class of residents	1
LGE [Member] | Maximum [Member]
Legal Matters - Cane Run Environmental Claims (Numeric) [Abstract]
Number of miles within plant that would include a class of residents	3
PPL Electric Utilities Corp [Member] | PPL Electric Additional Sites [Member]
Claim By Former Affiliate [Abstract]
Accrual for Environmental Loss Contingencies | $				$ 10	$ 10
LG And E And KU Energy LLC [Member] | LGE [Member]
Legal Matters - Cane Run Environmental Claims (Numeric) [Abstract]
Number of residents that filed class action suit | resident			6
Number of remaining unresolved Clean Air Act violation claims after July 2014 court ruling | claim		1
LG And E And KU Energy LLC [Member] | LGE [Member] | Minimum [Member]
Legal Matters - Cane Run Environmental Claims (Numeric) [Abstract]
Number of miles within plant that would include a class of residents	1
LG And E And KU Energy LLC [Member] | LGE [Member] | Maximum [Member]
Legal Matters - Cane Run Environmental Claims (Numeric) [Abstract]
Number of miles within plant that would include a class of residents	3
Louisville Gas And Electric Co [Member]
Legal Matters - Cane Run Environmental Claims (Numeric) [Abstract]
Number of residents that filed class action suit | resident			6
Number of remaining unresolved Clean Air Act violation claims after July 2014 court ruling | claim		1
Louisville Gas And Electric Co [Member] | Minimum [Member]
Legal Matters - Cane Run Environmental Claims (Numeric) [Abstract]
Number of miles within plant that would include a class of residents	1
Louisville Gas And Electric Co [Member] | Maximum [Member]
Legal Matters - Cane Run Environmental Claims (Numeric) [Abstract]
Number of miles within plant that would include a class of residents	3