Postretirement Benefit Obligations - Schedule of Net Benefit Costs (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
Postemployment Benefits [Abstract]
Postretirement benefits service cost	$ 0	$ 0	$ 1	$ 1	$ 2
Interest cost	8	9	17	27	33
Expected return on plan assets	(8)	(11)	(17)	(33)	(35)
Amortization of:
Net loss	0	1	0	2	0
Postretirement benefit (gain) loss, net	0	(1)	0	(4)	(2)
Net periodic defined benefit cost (credit)	$ 0	$ (1)	$ 1	$ (3)	$ 0