Pension and Other Postretirement Benefits - Components of Net Periodic Benefit Cost (Detail) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost		$ 3	$ 2	$ 8	$ 7
Interest cost	[1]	27	27	81	87
Expected return on plan assets	[1]	(34)	(35)	(104)	(111)
Recognized net actuarial loss	[1]	7	7	23	21
Curtailments	[2]			1
Settlements	[2]			(1)	21
Net periodic benefit cost		3	1	8	25
Other Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost		1		2	2
Interest cost	[1]	6	7	18	20
Recognized net actuarial loss	[1]	1	1	4	3
Amortization of prior service benefit	[1]	(3)	(3)	(10)	(10)
Net periodic benefit cost		$ 5	$ 5	$ 14	$ 15

[1] These amounts were reported in Other expenses, net on the accompanying Statement of Consolidated Operations (see Note P).

[2] These amounts were reported in Restructuring and other charges, net on the accompanying Statement of Consolidated Operations and Cash Flows.