Postretirement Benefit Plans - Amounts Recognized on Balance Sheets Related to Qualified Defined Benefit Pension Plans and Retiree Medical and Life Insurance Plans (Detail) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Defined Benefit Plan Disclosure [Line Items]
Accrued pension liabilities	$ (5,472)	$ (8,319)
Qualified Defined  Benefit Pension Plans
Defined Benefit Plan Disclosure [Line Items]
Other noncurrent assets	2	64
Accrued pension liabilities	(5,472)	(8,319)
Net (unfunded) funded status of the plans	(5,470)	(8,255)
Retiree Medical and Life Insurance Plans
Defined Benefit Plan Disclosure [Line Items]
Other noncurrent assets	297	330
Accrued pension liabilities	0	0
Net (unfunded) funded status of the plans	$ 297	$ 330