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Asset Retirement Obligations (Details)
$ in Millions
6 Months Ended
Jun. 30, 2021
USD ($)
Asset Retirement Obligation [Roll Forward]  
Balance at Beginning of Period $ 182
Accretion 8
Changes in estimated timing or cost 15
Obligations settled (33)
Balance at End of Period 172
Louisville Gas And Electric Co [Member]  
Asset Retirement Obligation [Roll Forward]  
Balance at Beginning of Period 67
Accretion 3
Changes in estimated timing or cost 5
Obligations settled (15)
Balance at End of Period 60
Kentucky Utilities Co [Member]  
Asset Retirement Obligation [Roll Forward]  
Balance at Beginning of Period 115
Accretion 5
Changes in estimated timing or cost 10
Obligations settled (18)
Balance at End of Period $ 112