Revenue (Details) $ in Millions		3 Months Ended
		Mar. 31, 2022 USD ($) company MW	Mar. 31, 2021 USD ($)
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers		$ 2,970	$ 2,743
Total revenues	[1]	2,989	2,726
Other Non-Customer Revenue
Disaggregation of Revenue [Line Items]
Late payment charges		10	9
Distribution services
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers		1,320	1,313
Retail generation
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers		1,077	923
Wholesale sales
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers		96	73
Transmission
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers		451	401
Other
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers		26	33
ARP
Disaggregation of Revenue [Line Items]
Total revenues			(27)
Other non-customer revenue
Disaggregation of Revenue [Line Items]
Total revenues		19	10
Derivative revenue | Other Non-Customer Revenue
Disaggregation of Revenue [Line Items]
Total revenues		9
Regulated Distribution
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers		$ 2,442	2,274
Number of existing utility operating companies | company		10
Megawatts of net demonstrated capacity of competitive segment | MW		3,580
Utility customer payment period		30 days
Regulated Distribution | Residential
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers		$ 1,542	1,457
Regulated Distribution | Commercial
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers		597	541
Regulated Distribution | Industrial
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers		283	258
Regulated Distribution | Other
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers		20	18
Regulated Transmission
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers		451	401
Regulated Transmission | ATSI
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers		217	206
Regulated Transmission | TrAIL
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers		63	59
Regulated Transmission | MAIT
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers		79	67
Regulated Transmission | JCP&L
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers		60	36
Regulated Transmission | MP, PE and WP
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers		32	33
Operating Segments | Regulated Distribution
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers		2,558	2,376
Total revenues		2,589	2,370
Operating Segments | Regulated Distribution | Distribution services
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers		1,348	1,339
Operating Segments | Regulated Distribution | Retail generation
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers		1,094	935
Operating Segments | Regulated Distribution | Wholesale sales
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers		90	69
Operating Segments | Regulated Distribution | Transmission
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers		0	0
Operating Segments | Regulated Distribution | Other
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers		26	33
Operating Segments | Regulated Distribution | ARP
Disaggregation of Revenue [Line Items]
Total revenues			(27)
Operating Segments | Regulated Distribution | Other non-customer revenue
Disaggregation of Revenue [Line Items]
Total revenues		31	21
Operating Segments | Regulated Transmission
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers		451	401
Total revenues		453	405
Operating Segments | Regulated Transmission | Distribution services
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers		0	0
Operating Segments | Regulated Transmission | Retail generation
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers		0	0
Operating Segments | Regulated Transmission | Wholesale sales
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers		0	0
Operating Segments | Regulated Transmission | Transmission
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers		451	401
Operating Segments | Regulated Transmission | Other
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers		0	0
Operating Segments | Regulated Transmission | ARP
Disaggregation of Revenue [Line Items]
Total revenues			0
Operating Segments | Regulated Transmission | Other non-customer revenue
Disaggregation of Revenue [Line Items]
Total revenues		2	4
Corporate/Other and Reconciling Adjustments
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers		(39)	(34)
Total revenues		(53)	(49)
Corporate/Other and Reconciling Adjustments | Distribution services
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers		(28)	(26)
Corporate/Other and Reconciling Adjustments | Retail generation
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers		(17)	(12)
Corporate/Other and Reconciling Adjustments | Wholesale sales
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers		6	4
Corporate/Other and Reconciling Adjustments | Transmission
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers		0	0
Corporate/Other and Reconciling Adjustments | Other
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers		0	0
Corporate/Other and Reconciling Adjustments | ARP
Disaggregation of Revenue [Line Items]
Total revenues			0
Corporate/Other and Reconciling Adjustments | Other non-customer revenue
Disaggregation of Revenue [Line Items]
Total revenues		$ (14)	$ (15)

[1] Includes excise and gross receipts tax collections of $103 million and $95 million during the three months ended March 31, 2022 and 2021, respectively.