Retirement Plans - Components of Net Periodic Benefit Cost for Pension Plans & Postretirement Medical Plan (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Defined Benefit Plan Disclosure [Line Items]
Settlement loss	$ 9	$ 0	$ 93
Net non-service pension (income) costs included in Other, net	(75)	(59)	55
Pension Plans
Defined Benefit Plan Disclosure [Line Items]
Service cost	51	50	44
Interest cost	55	73	89
Expected return on plan assets	(197)	(180)	(180)
Amortization of unrecognized net actuarial losses (gains)	58	48	52
Settlement loss	9	0	93
Curtailment gain	0	0	0
Net Periodic Benefit Cost	(24)	(9)	98
Postretirement Medical Plan
Defined Benefit Plan Disclosure [Line Items]
Service cost	3	3	2
Interest cost	1	1	2
Expected return on plan assets	0	0	0
Amortization of unrecognized net actuarial losses (gains)	(1)	(1)	(1)
Settlement loss	0	0	0
Curtailment gain	0	0	0
Net Periodic Benefit Cost	$ 3	$ 3	$ 3