Pension and Other Postretirement Benefits - Components of Net Periodic Benefit Cost (Detail) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost		$ 2	$ 3	$ 7	$ 10
Interest cost	[1]	27	24	87	78
Expected return on plan assets	[1]	(35)	(35)	(111)	(123)
Recognized net actuarial loss	[1]	7	19	21	74
Settlements	[2]		626	21	626
Net periodic benefit cost		1	637	25	665
Other Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost			1	2	3
Interest cost	[1]	7	4	20	12
Recognized net actuarial loss	[1]	1	5	3	14
Amortization of prior service cost	[1]	(3)	(4)	(10)	(11)
Net periodic benefit cost		$ 5	$ 6	$ 15	$ 18

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

[2] These amounts were reported in Restructuring and other charges, net on the accompanying Statements of Consolidated Operations (see Note D) and Cash Flows.