Employee Benefit Plans (Components of Net Periodic Benefit Cost (Credit) (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 2	$ 2	$ 4	$ 4
Interest cost	8	8	17	16
Expected return on assets	(11)	(10)	(21)	(19)
Amortization of actuarial losses	2	2	3	4
Net periodic benefit cost (credit)	1	2	3	5
Other Postretirement Benefits Plan
Defined Benefit Plan Disclosure [Line Items]
Service cost	0	1	0	1
Interest cost	2	2	4	4
Expected return on assets	0	0	0	0
Amortization of actuarial losses	(1)	(1)	(2)	(2)
Net periodic benefit cost (credit)	$ 1	$ 2	$ 2	$ 3