Postretirement Plans (Components Of Net Periodic Benefit Cost) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 1,764	$ 1,661	$ 1,886
Interest cost	2,990	3,058	2,906
Expected return on plan assets	(4,031)	(4,169)	(3,874)
Amortization of prior service costs/(credits)	196	177	196
Recognized net actuarial loss	1,577	1,020	2,231
Settlement/curtailment/other losses	290	461	104
Net periodic benefit cost	2,786	2,208	3,449
Net periodic benefit cost included in Earnings from operations	2,366	3,215	3,036
Other Postretirement Benefits Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	140	129	148
Interest cost	248	289	263
Expected return on plan assets	(8)	(8)	(6)
Amortization of prior service costs/(credits)	(136)	(144)	(180)
Recognized net actuarial loss	31	8	$ 95
Settlement/curtailment/other losses	10	1
Net periodic benefit cost	285	275	$ 320
Net periodic benefit cost included in Earnings from operations	$ 288	$ 287	$ 353