Significant Accounting Policies - Reclassifications Out of Accumulated Other Comprehensive Loss (Detail) - Pension and Postretirement Benefit Plans - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Amounts reclassified from accumulated other comprehensive loss, net of tax	$ 2	$ 1	$ 4	$ 3
Reclassification out of Accumulated Other Comprehensive Income
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Amortization of prior service cost	2	1	5	4
Amortization of Actuarial loss	0	0	1	0
Tax effect	0	0	(2)	(1)
Amounts reclassified from accumulated other comprehensive loss, net of tax	2	1	4	3
Reclassification out of Accumulated Other Comprehensive Income | Other Nonoperating Income, Net
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Total reclassifications out of accumulated other comprehensive loss before taxes	$ 2	$ 1	$ 6	$ 4