Employee Retirement Plans (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2026	Mar. 31, 2025
Pension benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 26	$ 24
Interest cost	45	47
Expected return on plan assets	(52)	(50)
Amortization of prior service cost (credit)	1	1
Total pension and postretirement benefit expense (income)	20	22
Postretirement benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	1	1
Interest cost	3	4
Amortization of actuarial net gain	(6)	(6)
Amortization of prior service cost (credit)	(1)	(2)
Total pension and postretirement benefit expense (income)	$ (3)	$ (3)