Postretirement Plans (Schedule Of Changes In The Benefit Obligation, Plan Assets And Funded Status Of Both Pensions And OPB) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Company contribution	$ 3,500
Defined Benefit Plan, Amounts for Asset (Liability) Recognized in Statement of Financial Position [Abstract]
Accrued pension plan liability, net	(16,471)	$ (19,943)
Pension Plans [Member]
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Beginning balance	76,745	74,388
Service cost	402	604	$ 1,764
Interest cost	2,991	3,050	2,990
Plan participants’ contributions		1
Amendments	(7)	6
Actuarial loss/(gain)	5,653	2,669
Settlement/curtailment/other	(751)	(63)
Gross benefits paid	(4,658)	(3,903)
Exchange rate adjustment	18	(7)
Ending balance	80,393	76,745	74,388
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Beginning balance at fair value	56,692	56,514
Actual return on plan assets	8,552	3,885
Company contribution	4,025	113
Plan participants’ contributions		1
Settlement payments	(744)	(24)
Benefits paid	(4,530)	(3,791)
Exchange rate adjustment	16	(6)
Ending balance at fair value	64,011	56,692	56,514
Defined Benefit Plan, Amounts for Asset (Liability) Recognized in Statement of Financial Position [Abstract]
Other assets	218	3
Other accrued liabilities	(129)	(113)
Accrued pension plan liability, net	(16,471)	(19,943)
Net amount recognized	(16,382)	(20,053)
Other Postretirement Benefits Plans [Member]
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Beginning balance	6,431	7,138
Service cost	106	128	140
Interest cost	229	262	248
Amendments	(35)	(57)
Actuarial loss/(gain)	(204)	(612)
Settlement/curtailment/other
Gross benefits paid	(481)	(469)
Subsidies	33	37
Exchange rate adjustment	6	4
Ending balance	6,085	6,431	7,138
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Beginning balance at fair value	134	132
Actual return on plan assets	15	7
Company contribution	6	6
Plan participants’ contributions	4	7
Benefits paid	(16)	(18)
Ending balance at fair value	143	134	$ 132
Defined Benefit Plan, Amounts for Asset (Liability) Recognized in Statement of Financial Position [Abstract]
Other accrued liabilities	(397)	(381)
Accrued retiree health care	(5,545)	(5,916)
Net amount recognized	$ (5,942)	$ (6,297)