Segment and Related Information (Income Statement and Balance Sheet Data) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Income Statement Data
Operating Revenues from external customers	$ 5,783,000,000	$ 5,474,000,000	$ 5,602,000,000
Depreciation	1,082,000,000	1,022,000,000	949,000,000
Amortization	39,000,000	58,000,000	58,000,000
Interest Expense	918,000,000	634,000,000	621,000,000
Income Before Income Taxes	521,000,000	954,000,000	919,000,000
Income Taxes	503,000,000	314,000,000	183,000,000
Deferred income taxes and investment tax credits	87,000,000	169,000,000	169,000,000
Net income	(1,480,000,000)	1,469,000,000	1,746,000,000
Cash Flow Data
Expenditures for long-lived assets	1,979,000,000	2,278,000,000	2,250,000,000
Balance Sheet Data
Total Assets	33,223,000,000	48,116,000,000
Kentucky Regulated [Member]
Income Statement Data
Operating Revenues from external customers	3,348,000,000	3,106,000,000	3,206,000,000
Depreciation	647,000,000	606,000,000	547,000,000
Amortization	15,000,000	19,000,000	27,000,000
Interest Expense	249,000,000	300,000,000	298,000,000
Income Before Income Taxes	562,000,000	516,000,000	530,000,000
Income Taxes	94,000,000	98,000,000	94,000,000
Deferred income taxes and investment tax credits	272,000,000	64,000,000	82,000,000
Net income	468,000,000	418,000,000	436,000,000
Cash Flow Data
Expenditures for long-lived assets	1,026,000,000	966,000,000	1,097,000,000
Balance Sheet Data
Total Assets	16,360,000,000	15,943,000,000
Segment Information (Numeric) [Abstract]
Financing Costs Allocated to Segment, Net of Tax		32,000,000	32,000,000
Income Taxes Allocated to Segment		8,000,000	9,000,000
Pennsylvania Regulated [Member]
Income Statement Data
Operating Revenues from external customers	2,402,000,000	2,330,000,000	2,358,000,000
Depreciation	424,000,000	403,000,000	386,000,000
Amortization	19,000,000	26,000,000	24,000,000
Interest Expense	162,000,000	172,000,000	169,000,000
Income Before Income Taxes	599,000,000	664,000,000	607,000,000
Income Taxes	154,000,000	167,000,000	149,000,000
Deferred income taxes and investment tax credits	79,000,000	82,000,000	90,000,000
Net income	445,000,000	497,000,000	458,000,000
Cash Flow Data
Expenditures for long-lived assets	904,000,000	1,154,000,000	1,121,000,000
Balance Sheet Data
Total Assets	13,336,000,000	12,347,000,000
Corporate And Other [Member]
Income Statement Data
Operating Revenues from external customers	33,000,000	38,000,000	38,000,000
Depreciation	11,000,000	13,000,000	16,000,000
Amortization	5,000,000	13,000,000	7,000,000
Interest Expense	507,000,000	162,000,000	154,000,000
Income Before Income Taxes	(640,000,000)	(226,000,000)	(218,000,000)
Income Taxes	255,000,000	49,000,000	(60,000,000)
Deferred income taxes and investment tax credits	(264,000,000)	23,000,000	(3,000,000)
Net income	(895,000,000)	(275,000,000)	(158,000,000)
Cash Flow Data
Expenditures for long-lived assets	49,000,000	158,000,000	32,000,000
Balance Sheet Data
Total Assets	3,527,000,000	843,000,000
Discontinued Operations Segment
Income Statement Data
Net income	(1,498,000,000)	829,000,000	$ 1,010,000,000
Balance Sheet Data
Total Assets	$ 0	$ 18,983,000,000