Income Taxes (Tax Effects Of Temporary Differences Between Reported Earnings And Taxable Earnings) (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Income Tax Disclosure [Abstract]
Retirement benefits	$ 570	$ 1,042
Lease liabilities	370	373
Tax loss and credit carryforwards	294	311
Salaries and wages	236	259
Workers' compensation	161	167
Other	365	373
Deferred assets	1,996	2,525
Valuation allowance	(258)	(273)
Net deferred assets	1,738	2,252
Intangible assets	(1,059)	(1,067)
Property, plant and equipment	(367)	(379)
Contract accounting methods	(259)	(311)
Property, plant and equipment	(412)	(270)
Capital Construction Fund qualified ships	(57)	(59)
Other	(411)	(590)
Deferred liabilities	(2,565)	(2,676)
Net deferred tax liability	$ (827)	$ (424)

Deferred Tax Assets, Deferred Tax Expense, Right-of-Use Asset

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