Significant Accounting Policies - Changes in Accumulated Other Comprehensive Loss Net of Tax (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance, Total Equity	$ 8,036	$ 7,173
Other comprehensive earnings (loss), net of tax	0	1
Ending Balance, Total Equity	8,877	7,178
Pension and Postretirement Benefit Plans
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance, Total Equity	(48)	(36)
Amounts reclassified from accumulated other comprehensive loss, net of tax	1	1
Other comprehensive earnings (loss), net of tax	1	1
Ending Balance, Total Equity	(47)	(35)
Foreign Currency
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance, Total Equity	(1)	(2)
Other comprehensive loss before reclassifications, net of tax	(1)
Other comprehensive earnings (loss), net of tax	(1)
Ending Balance, Total Equity	(2)	(2)
Accumulated Other Comprehensive Loss
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance, Total Equity	(49)	(38)
Other comprehensive loss before reclassifications, net of tax	(1)
Amounts reclassified from accumulated other comprehensive loss, net of tax	1	1
Other comprehensive earnings (loss), net of tax		1
Ending Balance, Total Equity	$ (49)	$ (37)