Pension Benefits - Schedule of Components of Net Periodic Benefit Cost (Detail) - Pension - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 9	$ 10	$ 18	$ 19
Interest cost	14	15	29	28
Expected return on assets	(20)	(21)	(41)	(39)
Amortization of prior service cost	1	2	3	3
Amortization of actuarial loss	0	0	1	0
Net periodic benefit cost (credit)	$ 4	$ 6	$ 10	$ 11