Income Taxes - Components of Federal and Foreign Deferred Tax Assets and Liabilities (Detail) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Deferred tax assets related to:
Accrued compensation and benefits	$ 659	$ 584
Pensions	3,057	2,623
Other postretirement benefit obligations	71	148
Contract accounting methods	349	539
Foreign company operating losses and credits	49	38
Other	345	160
Valuation allowance	(28)	(20)
Deferred tax assets, net	4,502	4,072
Deferred tax liabilities related to:
Goodwill and purchased intangibles	330	296
Property, plant and equipment	340	296
Exchanged debt securities and other	525	294
Deferred tax liabilities	1,195	886
Net deferred tax assets	$ 3,307	$ 3,186