Income Taxes (Significant Components Of Deferred Tax Assets Net Of Deferred Tax Liabilities) (Details) - USD ($) $ in Millions		Dec. 31, 2017	Dec. 31, 2016
Valuation Allowance [Line Items]
Inventory and long-term contract methods of income recognition		$ (6,290)	$ (9,954)
Pension benefits		3,690	7,385
Retiree health care benefits		1,319	2,268
Fixed assets, intangibles and goodwill (net of valuation allowance of $16 and $16)		(1,259)	(2,007)
Other employee benefits		847	1,225
Customer and commercial financing		(369)	(730)
Accrued expenses and reserves		347	587
Net operating loss, credit and capital loss carryovers (net of valuation allowance of $53 and $79)(1)	[1]	299	277
Other		(82)	(57)
Net deferred tax (liabilities)/assets(2)	[2]	1,498	1,006
Valuation Allowance - Fixed assets, intangibles, and goodwill deferred tax assets		69	95
Valuation Allowance - Net operating loss, credit and capital loss carryovers		53	79
Deferred tax asset for net operating loss and credit carryovers each year through December 31, 2035		278
Deferred tax asset for net operating loss and credit carryovers indefinitely		21
Deferred tax assets related to Accumulated other comprehensive loss		4,636	7,701
Valuation Allowance, Property Plant and Equipment, Intangibles and Goodwill [Member]
Valuation Allowance [Line Items]
Valuation Allowance - Fixed assets, intangibles, and goodwill deferred tax assets		$ 16	$ 16

[1] Of the deferred tax asset for net operating loss and credit carryovers, $278 expires on or before December 31, 2036 and $21 may be carried over indefinitely.

[2] Included in the net deferred tax (liabilities)/assets as of December 31, 2017 and 2016 are deferred tax assets in the amounts of $4,636 and $7,701 related to Accumulated other comprehensive loss.