Pension And Other Postretirement Benefits (Long-Term Rates Of Pension And Other Postretirement Benefits) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Defined Benefit Plan Disclosure [Line Items]
Total recorded in other comprehensive income	$ (1,279)	$ (2,287)	$ (5,535)
U.S. [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate	4.25%	4.25%	4.00%
Long-term rate of return on funded assets	6.50%	6.50%	7.00%
Long-term rate of compensation increase	5.75%	5.75%	5.75%
Service cost	$ 784	$ 810	$ 864
Interest cost	798	793	785
Expected return on plan assets	(775)	(726)	(830)
Amortization of actuarial loss/(gain)	438	492	544
Amortization of prior service cost	5	6	6
Net pension enhancement and curtailment/settlement cost	609	319	499
Net periodic benefit cost	1,859	1,694	1,868
Net actuarial loss/(gain)	(324)	27	592
Amortization of actuarial (loss)/gain	(1,047)	(811)	(1,043)
Amortization of prior service (cost)/credit	(5)	(6)	(6)
Total recorded in other comprehensive income	(1,376)	(790)	(457)
Total recorded in net periodic benefit cost and other comprehensive income, before tax	$ 483	$ 904	$ 1,411
Pension Benefits - Non-U.S. [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate	3.00%	3.60%	3.10%
Long-term rate of return on funded assets	5.20%	5.25%	5.90%
Long-term rate of compensation increase	4.00%	4.80%	5.30%
Service cost	$ 596	$ 585	$ 689
Interest cost	772	844	850
Expected return on plan assets	(1,000)	(927)	(1,094)
Amortization of actuarial loss/(gain)	476	536	730
Amortization of prior service cost	47	54	87
Net pension enhancement and curtailment/settlement cost	19	2	22
Net periodic benefit cost	910	1,094	1,284
Net actuarial loss/(gain)	(191)	(156)	(1,375)
Amortization of actuarial (loss)/gain	(495)	(538)	(752)
Prior service cost/(credit)	111	32	(401)
Amortization of prior service (cost)/credit	(47)	(54)	(87)
Foreign exchange rate changes	559	(108)	(1,126)
Total recorded in other comprehensive income	(63)	(824)	(3,741)
Total recorded in net periodic benefit cost and other comprehensive income, before tax	$ 847	$ 270	$ (2,457)
Other Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate	4.25%	4.25%	4.00%
Long-term rate of return on funded assets	6.50%	6.50%	7.00%
Long-term rate of compensation increase	5.75%	5.75%	5.75%
Service cost	$ 129	$ 153	$ 170
Interest cost	317	344	346
Expected return on plan assets	(24)	(25)	(28)
Amortization of actuarial loss/(gain)	96	153	206
Amortization of prior service cost	(33)	(30)	(24)
Net periodic benefit cost	485	595	670
Net actuarial loss/(gain)	215	(555)	(589)
Amortization of actuarial (loss)/gain	(96)	(153)	(206)
Prior service cost/(credit)			(535)
Amortization of prior service (cost)/credit	33	30	24
Foreign exchange rate changes	8	5	(31)
Total recorded in other comprehensive income	160	(673)	(1,337)
Total recorded in net periodic benefit cost and other comprehensive income, before tax	$ 645	$ (78)	$ (667)