Segments - Segments and Reconciliation (Details) - USD ($) $ in Millions	1 Months Ended	2 Months Ended	3 Months Ended	5 Months Ended	6 Months Ended
	Jun. 30, 2023	May 17, 2023	Jun. 30, 2024	May 17, 2023	Jun. 30, 2024
Segment Reporting Information [Line Items]
Operating revenues	$ 301	$ 137	$ 489	$ 1,210	$ 998
Interest expense and other finance charges	33	59	62	163	121
Capital expenditures	34	57	14	187	80
Adjusted EBITDA	93	47	100	725	418
Corporate and Eliminations
Segment Reporting Information [Line Items]
Operating revenues	(24)	(22)	(7)	(37)	(81)
Interest expense and other finance charges	33	59	62	163	121
Capital expenditures	1	0	0	2	0
PJM
Segment Reporting Information [Line Items]
Adjusted EBITDA	72	44	95	688	375
PJM | Operating Segments
Segment Reporting Information [Line Items]
Operating revenues	355	78	438	1,054	871
Interest expense and other finance charges	0	0	0	0	0
Capital expenditures	23	38	14	132	66
Adjusted EBITDA	72	44	95	688	375
Other
Segment Reporting Information [Line Items]
Adjusted EBITDA	21	3	5	37	43
Other | Operating Segments
Segment Reporting Information [Line Items]
Operating revenues	(30)	81	58	193	208
Interest expense and other finance charges	0	0	0	0	0
Capital expenditures	10	19	0	53	14
Adjusted EBITDA	$ 21	$ 3	$ 5	$ 37	$ 43