Benefit Plans - Schedule of Components of Net Cost (Benefit) for Pension and Other Postretirement Plans (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Defined Benefit Plan Disclosure [Line Items]
Costs and expenses	$ (23)	$ 7	$ (7)	$ 20
Remeasurement (gains) losses	(9)	(40)	(11)	(93)
Total net benefit	(32)	(33)	(18)	(73)
Pension benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	(7)	32	26	65
Interest cost	58	58	116	118
Expected return on plan assets	(76)	(79)	(153)	(156)
Costs and expenses	(25)	11	(11)	27
Remeasurement of projected benefit obligation	(68)	(68)	(93)	55
Remeasurement of plan assets	60	30	85	(150)
Remeasurement (gains) losses	(8)	(38)	(8)	(95)
Total net benefit	(33)	(27)	(19)	(68)
Postretirement benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	0	0	0	0
Interest cost	3	2	5	5
Amortization of prior service credit	(1)	(6)	(1)	(12)
Costs and expenses	2	(4)	4	(7)
Remeasurement of projected benefit obligation	(1)	(2)	(3)	2
Remeasurement of plan assets	0	0	0	0
Remeasurement (gains) losses	(1)	(2)	(3)	2
Total net benefit	$ 1	$ (6)	$ 1	$ (5)