Postretirement Benefit Plans - Additional Information (Detail) shares in Millions, $ in Millions	3 Months Ended	12 Months Ended
	Dec. 31, 2023 USD ($) participant shares	Dec. 31, 2023 USD ($) shares	Dec. 31, 2022 USD ($) shares	Dec. 31, 2021 USD ($)	Jun. 26, 2022 USD ($) retiree	Sep. 26, 2021 USD ($) retiree
Defined Benefit Plan Disclosure [Line Items]
Settlement payments	$ 414
Number of participants | participant	6,500
Outstanding pension benefit obligations and related plan assets					$ 4,300
Non-cash, non-operating pension settlement charge			$ 1,500	$ 1,700
Assets set aside expected to be used to pay obligations of defined benefit pension plans and retiree medical and life insurance plans	$ 24,515	$ 24,515	24,884
Contributions made to defined contribution plans		$ 1,200	$ 1,100	1,100
Shares of our stock held in defined contribution plans we sponsor (in shares) | shares	26.6	26.6	27.4
Hedge funds
Defined Benefit Plan Disclosure [Line Items]
Assets set aside expected to be used to pay obligations of defined benefit pension plans and retiree medical and life insurance plans	$ 847	$ 847	$ 689
Minimum | Hedge funds
Defined Benefit Plan Disclosure [Line Items]
Fair value, investments, entities that calculate net asset value per share, investment redemption, notice period		1 month
Commingled equity funds
Defined Benefit Plan Disclosure [Line Items]
Fair value, investments, entities that calculate net asset value per share, investment redemption, notice period		90 days
Private equity funds | Minimum
Defined Benefit Plan Disclosure [Line Items]
Fair value, investments, entities that calculate net asset value per share, investment redemption, notice period		8 years
Private equity funds | Maximum
Defined Benefit Plan Disclosure [Line Items]
Fair value, investments, entities that calculate net asset value per share, investment redemption, notice period		12 years
Real estate funds | Minimum
Defined Benefit Plan Disclosure [Line Items]
Fair value, investments, entities that calculate net asset value per share, investment redemption, notice period		8 years
Real estate funds | Maximum
Defined Benefit Plan Disclosure [Line Items]
Fair value, investments, entities that calculate net asset value per share, investment redemption, notice period		10 years
Qualified Defined  Benefit Pension Plans
Defined Benefit Plan Disclosure [Line Items]
Settlement payments		$ 414	4,309
Actual return on plan assets (percent)	7.00%	7.00%
Gross benefit obligation	$ 28,959	$ 28,959	28,698	43,447
Assets set aside expected to be used to pay obligations of defined benefit pension plans and retiree medical and life insurance plans	22,800	22,800	23,228	35,192
Net actuarial (losses) gains	10,999	10,999	10,287
Qualified Plan | Qualified Defined  Benefit Pension Plans
Defined Benefit Plan Disclosure [Line Items]
Outstanding pension benefit obligations and related plan assets						$ 4,900
Number of retirees and beneficiaries | retiree					13,600	18,000
Nonqualified Plan
Defined Benefit Plan Disclosure [Line Items]
Gross benefit obligation	1,000	1,000	1,000
Assets set aside expected to be used to pay obligations of defined benefit pension plans and retiree medical and life insurance plans	615	615	595
Net actuarial (losses) gains	$ (347)	(347)	(331)
Benefit plan expense		$ 64	$ 81	$ 56