Significant Accounting Policies - Changes in Accumulated Other Comprehensive Loss Net of Tax (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance, Total Equity	$ 8,877	$ 7,177	$ 8,036	$ 7,173
Other comprehensive earnings (loss), net of tax	1	2	1	3
Ending Balance, Total Equity	8,840	7,424	8,840	7,424
Pension and Postretirement Benefit Plans
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance, Total Equity	(47)	(35)	(48)	(36)
Amounts reclassified from accumulated other comprehensive loss, net of tax	1	1	2	2
Other comprehensive earnings (loss), net of tax	1	1	2	2
Ending Balance, Total Equity	(46)	(34)	(46)	(34)
Foreign Currency
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance, Total Equity	(2)	(2)	(1)	(2)
Other comprehensive earnings (loss) before reclassifications, net of tax		1	(1)	1
Other comprehensive earnings (loss), net of tax		1	(1)	1
Ending Balance, Total Equity	(2)	(1)	(2)	(1)
Accumulated Other Comprehensive Loss
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance, Total Equity	(49)	(37)	(49)	(38)
Other comprehensive earnings (loss) before reclassifications, net of tax		1	(1)	1
Amounts reclassified from accumulated other comprehensive loss, net of tax	1	1	2	2
Other comprehensive earnings (loss), net of tax	1	2	1	3
Ending Balance, Total Equity	$ (48)	$ (35)	$ (48)	$ (35)