Benefit Plans - Schedule of Components of Net Cost (Benefit) for Pension and Other Postretirement Plans (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Defined Benefit Plan Disclosure [Line Items]
Costs and expenses	$ 13	$ 11	$ 6	$ 31
Remeasurement (gains) losses	26	149	15	56
Total net cost	39	160	21	87
Pension benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	26	34	52	99
Interest cost	59	58	175	176
Expected return on plan assets	(74)	(78)	(227)	(234)
Costs and expenses	11	14	0	41
Remeasurement of projected benefit obligation	233	(211)	140	(156)
Remeasurement of plan assets	(214)	369	(129)	219
Remeasurement (gains) losses	19	158	11	63
Total net cost	30	172	11	104
Postretirement benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	0	0	0	0
Interest cost	2	3	7	8
Amortization of prior service credit	0	(6)	(1)	(18)
Costs and expenses	2	(3)	6	(10)
Remeasurement of projected benefit obligation	7	(9)	4	(7)
Remeasurement of plan assets	0	0	0	0
Remeasurement (gains) losses	7	(9)	4	(7)
Total net cost	$ 9	$ (12)	$ 10	$ (17)