Pension Benefits - Schedule of Components of Net Periodic Benefit Cost (Detail) - Pension - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 10	$ 8	$ 29	$ 25
Interest cost	14	13	41	39
Expected return on assets	(20)	(18)	(59)	(54)
Amortization of prior service cost	2	2	5	4
Amortization of actuarial loss	0	0	1	0
Net periodic benefit cost	$ 6	$ 5	$ 17	$ 14