Income Taxes - Components of Federal and Foreign Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Deferred tax assets related to:
Pensions	$ 1,485	$ 1,340
Accrued compensation and benefits	731	718
Contract accounting methods	508	510
Research and development expenditures	1,251	2,268
Foreign company operating losses and credits	19	20
Other	487	471
Valuation allowance	(32)	(31)
Deferred tax assets, net	4,449	5,296
Deferred tax liabilities related to:
Goodwill and intangible assets	494	449
Property, plant and equipment	415	503
Other	597	605
Deferred tax liabilities	1,506	1,557
Net deferred tax assets	$ 2,943	$ 3,739