Significant Accounting Policies - Reclassifications Out of Accumulated Other Comprehensive Loss (Detail) - Pension and Postretirement Benefit Plans - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Earnings from Continuing Operations	$ 1	$ 1
Reclassification out of Accumulated Other Comprehensive Income
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Tax effect	(1)	(1)
Earnings from Continuing Operations	1	1
Reclassification out of Accumulated Other Comprehensive Income | Other Nonoperating Income, Net
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Amortization of prior service cost	$ 2	$ 2