Postretirement Benefit Plans - Schedule of Net Periodic Benefit Costs (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Defined Benefit Plan Disclosure [Line Items]
Pension settlement charge	$ (1,470)	$ (1,665)	$ 0
Qualified Defined  Benefit Pension Plans
Defined Benefit Plan Disclosure [Line Items]
Service cost	(87)	(106)	(101)
Interest cost	(1,289)	(1,220)	(1,538)
Expected return on plan assets	1,854	2,146	2,264
Recognized net actuarial (losses) gains	(425)	(902)	(849)
Amortization of prior service credits (costs)	359	349	342
Pension settlement charge	(1,470)	(1,665)	0
Non-service FAS (expense) income	(971)	(1,292)	219
Total FAS (expense) income	(1,058)	(1,398)	118
Retiree Medical and Life Insurance Plans
Defined Benefit Plan Disclosure [Line Items]
Service cost	(9)	(13)	(13)
Interest cost	(49)	(53)	(70)
Expected return on plan assets	136	141	127
Recognized net actuarial (losses) gains	46	0	4
Amortization of prior service credits (costs)	(27)	(37)	(39)
Pension settlement charge	0	0	0
Non-service FAS (expense) income	106	51	22
Total FAS (expense) income	$ 97	$ 38	$ 9