Postretirement Plans (Components Of Net Periodic Benefit Cost) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 1,649	$ 1,406	$ 1,176
Interest cost	3,005	3,116	3,002
Expected return on plan assets	(3,831)	(3,741)	(3,850)
Amortization of prior service costs	225	244	248
Recognized net actuarial loss	1,937	1,254	777
Settlement and curtailment loss	25	64	14
Net periodic benefit cost	3,010	2,343	1,367
Net periodic benefit cost included in Earnings from operations	2,407	1,648	1,101
Other Postretirement Benefits Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	146	221	121
Interest cost	313	484	404
Expected return on plan assets	(7)	(6)	(6)
Amortization of prior service costs	(197)	(96)	(78)
Recognized net actuarial loss	119	178	56
Settlement and curtailment loss	(1)	3
Net periodic benefit cost	373	784	497
Net periodic benefit cost included in Earnings from operations	$ 543	$ 692	$ 480