CAPITALIZATION - Schedule of Long Term Debt (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Debt Instrument [Line Items]
Repayments of debt	$ 537	$ 3,005	$ 532
Debt issuance costs	2
Debt issuance costs, after tax	1
Senior Notes
Debt Instrument [Line Items]
Open market discount	34
Open market discount, net	$ 27
3.50% Unsecured Notes Due March, 2023 | Promissory Notes | ME
Debt Instrument [Line Items]
Interest Rate	3.50%
Face amount of loan	$ 300
7.38% Unsecured Notes Due May, 2031 | Promissory Notes | FE
Debt Instrument [Line Items]
Interest Rate	7.38%
Face amount of loan	$ 194
7.38% Unsecured Notes Due May, 2031 | Senior Notes
Debt Instrument [Line Items]
Long-term debt and other long-term obligations	194
Repayments of debt	$ 228
5.29% Notes Due January, 2033 | First Mortgage Bond | WP
Debt Instrument [Line Items]
Interest Rate	5.29%
Face amount of loan	$ 50
5.39% Unsecured Notes Due February, 2033 | Promissory Notes | MAIT
Debt Instrument [Line Items]
Interest Rate	5.39%
Face amount of loan	$ 175
5.20% Unsecured Notes Due March, 2028 | Promissory Notes | ME
Debt Instrument [Line Items]
Interest Rate	5.20%
Face amount of loan	$ 425
5.15% Unsecured Notes Due March, 2026 | Promissory Notes | PN
Debt Instrument [Line Items]
Interest Rate	5.15%
Face amount of loan	$ 300
5.13% Unsecured Notes Due May, 2033 | Promissory Notes | ATSI
Debt Instrument [Line Items]
Interest Rate	5.13%
Face amount of loan	$ 150
4.00% Unsecured Convertible Notes Due May, 2026 | Unsecured Convertible Notes | FE
Debt Instrument [Line Items]
Interest Rate	4.00%
Face amount of loan	$ 1,500
5.64% Notes Due September, 2028 | First Mortgage Bond | PE
Debt Instrument [Line Items]
Interest Rate	5.64%
Face amount of loan	$ 100
5.73% Notes Due September, 2030 | First Mortgage Bond | PE
Debt Instrument [Line Items]
Interest Rate	5.73%
Face amount of loan	$ 50
5.85% Notes Due September, 2034 | First Mortgage Bond | MP
Debt Instrument [Line Items]
Interest Rate	5.85%
Face amount of loan	$ 400
4.10% Notes Due April, 2024 | Senior Notes
Debt Instrument [Line Items]
Interest Rate	4.10%
Long-term debt and other long-term obligations	$ 400
3.50%, Unsecured Notes Maturing Mar 2023 | Senior Notes
Debt Instrument [Line Items]
Interest Rate	3.50%
Long-term debt and other long-term obligations	$ 300