Pension and Other Postretirement Benefits - Components of Net Periodic Benefit Cost (Detail) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2023	Mar. 31, 2022
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost		$ 2	$ 3
Interest cost	[1]	31	27
Expected return on plan assets	[1]	(39)	(44)
Recognized net actuarial loss	[1]	7	28
Net periodic benefit cost		1	14
Other Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost		1	1
Interest cost	[1]	6	4
Recognized net actuarial loss	[1]	1	4
Amortization of prior service cost	[1]	(3)	(3)
Net periodic benefit cost		$ 5	$ 6

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