Shareholders' Equity (Accumulated other comprehensive income) (Details) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	[1]	$ (12,838)	$ (13,815)	$ (12,748)	$ (13,903)
OCI before reclassifications	[1]	(97)	103	(338)	(75)
Amounts reclassified from AOCI	[1]	140	292	291	558
Net current period Other comprehensive income/(loss)	[1]	43	395	(47)	483
Ending Balance	[1]	(12,795)	(13,420)	(12,795)	(13,420)
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, for Net Gain (Loss), Net of Tax		130	264	261	508
Other Comprehensive Income Loss Reclassification Adjustment From AOCI Pension And Other Postretirement Benefit Plans For Settlements And Curtailments And Net Gain Loss Net Of Tax			267		511
Other Comprehensive (Income) Loss, Reclassification Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, for for settlements, curtailments and net (gain) loss, Tax			(147)		(284)
Amortization of actuarial losses included in net periodic pension cost, tax		(73)	(145)	(145)	(282)
Currency Translation Adjustments [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance		(16)	(35)	(39)	53
OCI before reclassifications		(16)	44	7	(44)
Amounts reclassified from AOCI
Net current period Other comprehensive income/(loss)		(16)	44	7	(44)
Ending Balance		(32)	9	(32)	9
Unrealized Gains and Losses on Certain Investments [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance		(2)	(7)		(8)
OCI before reclassifications		1	3	(1)	4
Amounts reclassified from AOCI
Net current period Other comprehensive income/(loss)		1	3	(1)	4
Ending Balance		(1)	(4)	(1)	(4)
Unrealized Gains and Losses on Derivative Instruments [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance		(116)	(215)	(197)	(136)
OCI before reclassifications		(17)	25	41	(66)
Amounts reclassified from AOCI		20	16	43	28
Net current period Other comprehensive income/(loss)		3	41	84	(38)
Ending Balance		(113)	(174)	(113)	(174)
Defined Benefit Pension Plans and Other Postretirement Benefits [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance		(12,704)	(13,558)	(12,512)	(13,812)
OCI before reclassifications		(65)	31	(385)	31
Amounts reclassified from AOCI	[2]	120	276	248	530
Net current period Other comprehensive income/(loss)		55	307	(137)	561
Ending Balance		$ (12,649)	$ (13,251)	$ (12,649)	$ (13,251)

[1] Net of tax.

[2] Primarily relates to amortization of actuarial losses for the six months and three months ended June 30, 2015 totaling $511 and $267 (net of tax of ($284) and ($147)) and for the six and three months ended June 30, 2016 totaling $261 and $130 (net of tax of ($145) and ($73)). These are included in the net periodic pension cost of which a portion is allocated to production as inventoried costs. See Note 11.