REVENUE (Details) $ in Millions		12 Months Ended
		Dec. 31, 2021 USD ($) company MW	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers		$ 11,112	$ 10,701	$ 10,805
Total revenues	[1]	$ 11,132	10,790	11,035
Utility customer payment period		30 days
Other Non-Customer Revenue
Disaggregation of Revenue [Line Items]
Late payment charges		$ 36	31	37
Distribution services
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers		5,329	5,171	5,050
Total revenues		9,009	8,688	8,720
Retail generation
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers		3,680	3,517	3,670
Wholesale sales
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers		376	260	423
Transmission
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers		1,608	1,613	1,510
Total revenues		1,608	1,613	1,510
Other
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers		119	140	152
Total revenues		515	489	805
ARP
Disaggregation of Revenue [Line Items]
Total revenues		(27)	43	181
Other revenue
Disaggregation of Revenue [Line Items]
Total revenues		47	46	49
Derivative Revenue | Other Non-Customer Revenue
Disaggregation of Revenue [Line Items]
Total revenues		$ 11	14	8
Regulated Distribution
Disaggregation of Revenue [Line Items]
Number of existing utility operating companies | company		10
Megawatts of net demonstrated capacity of competitive segment (in MW's) | MW		3,580
Regulated Distribution | Retail generation
Disaggregation of Revenue [Line Items]
Total revenues		$ 9,163	8,836	8,860
Regulated Distribution | Retail generation | Residential
Disaggregation of Revenue [Line Items]
Total revenues		5,713	5,539	5,412
Regulated Distribution | Retail generation | Commercial
Disaggregation of Revenue [Line Items]
Total revenues		2,284	2,140	2,252
Regulated Distribution | Retail generation | Industrial
Disaggregation of Revenue [Line Items]
Total revenues		1,091	1,076	1,106
Regulated Distribution | Retail generation | Other
Disaggregation of Revenue [Line Items]
Total revenues		75	81	90
Regulated Transmission
Disaggregation of Revenue [Line Items]
Total revenues		1,608	1,613	1,510
Regulated Transmission | Other
Disaggregation of Revenue [Line Items]
Total revenues		124	134	130
Regulated Transmission | ATSI
Disaggregation of Revenue [Line Items]
Total revenues		799	804	754
Regulated Transmission | TrAIL
Disaggregation of Revenue [Line Items]
Total revenues		233	247	242
Regulated Transmission | MAIT
Disaggregation of Revenue [Line Items]
Total revenues		288	250	224
Regulated Transmission | JCP&L
Disaggregation of Revenue [Line Items]
Total revenues		164	178	160
Operating Segments | Regulated Distribution
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers		9,644	9,227	9,421
Total revenues		9,711	9,363	9,698
Reduction in revenue		3	2	16
Operating Segments | Regulated Distribution | Distribution services
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers		5,433	5,259	5,133
Operating Segments | Regulated Distribution | Distribution services | Ohio Stipulation
Disaggregation of Revenue [Line Items]
Rate refunds		38
Operating Segments | Regulated Distribution | Retail generation
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers		3,730	3,577	3,727
Operating Segments | Regulated Distribution | Wholesale sales
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers		362	251	411
Operating Segments | Regulated Distribution | Transmission
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers		0	0	0
Operating Segments | Regulated Distribution | Other
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers		119	140	150
Operating Segments | Regulated Distribution | ARP
Disaggregation of Revenue [Line Items]
Total revenues		(27)	43	181
Operating Segments | Regulated Distribution | Other revenue
Disaggregation of Revenue [Line Items]
Total revenues		94	93	96
Operating Segments | Regulated Transmission
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers		1,608	1,613	1,510
Total revenues		1,618	1,630	1,526
Reduction in revenue		(2)	7	19
Operating Segments | Regulated Transmission | Distribution services
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers		0	0	0
Operating Segments | Regulated Transmission | Retail generation
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers		0	0	0
Operating Segments | Regulated Transmission | Wholesale sales
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers		0	0	0
Operating Segments | Regulated Transmission | Transmission
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers		1,608	1,613	1,510
Operating Segments | Regulated Transmission | Other
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers		0	0	0
Operating Segments | Regulated Transmission | ARP
Disaggregation of Revenue [Line Items]
Total revenues		0	0	0
Operating Segments | Regulated Transmission | Other revenue
Disaggregation of Revenue [Line Items]
Total revenues		10	17	16
Corporate/Other and Reconciling Adjustments
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers		(140)	(139)	(126)
Total revenues		(197)	(203)	(189)
Corporate/Other and Reconciling Adjustments | Distribution services
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers		(104)	(88)	(83)
Corporate/Other and Reconciling Adjustments | Retail generation
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers		(50)	(60)	(57)
Corporate/Other and Reconciling Adjustments | Wholesale sales
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers		14	9	12
Corporate/Other and Reconciling Adjustments | Transmission
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers		0	0	0
Corporate/Other and Reconciling Adjustments | Other
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers		0	0	2
Reconciling Adjustments | ARP
Disaggregation of Revenue [Line Items]
Total revenues		0	0	0
Reconciling Adjustments | Other revenue
Disaggregation of Revenue [Line Items]
Total revenues		$ (57)	$ (64)	$ (63)

[1] Includes excise and gross receipts tax collections of $374 million, $362 million and $373 million in 2021, 2020 and 2019, respectively.