Shareholders' Equity (Accumulated other comprehensive income) (Details) - USD ($) $ in Millions		3 Months Ended				6 Months Ended
		Jun. 30, 2015		Jun. 30, 2014		Jun. 30, 2015	Jun. 30, 2014
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	[1]	$ (13,815)		$ (8,883)		$ (13,903)	$ (9,894)
OCI before reclassifications	[1]	103		60		(75)	688
Amounts reclassified from AOCI	[1]	292		164		558	547
Net current period Other comprehensive income/(loss)	[1]	395		224		483	1,235
Ending Balance	[1]	(13,420)		(8,659)		(13,420)	(8,659)
OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForSettlementsAndCurtailmentsAndNetGainLossNetOfTax		267		163		511	535
Other Comprehensive (Income) Loss, Reclassification Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, for for settlements, curtailments and net (gain) loss, Tax		(147)		(91)		(284)	(298)
Currency Translation Adjustments [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance		(35)		167		53	150
OCI before reclassifications		$ 44		$ 21		$ (44)	$ 38
Amounts reclassified from AOCI
Net current period Other comprehensive income/(loss)		$ 44		$ 21		$ (44)	$ 38
Ending Balance		9		188		9	188
Unrealized Gains and Losses on Certain Investments [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance		(7)		(6)		(8)	(8)
OCI before reclassifications		$ 3		$ 1		$ 4	$ 3
Amounts reclassified from AOCI
Net current period Other comprehensive income/(loss)		$ 3		$ 1		$ 4	$ 3
Ending Balance		(4)		(5)		(4)	(5)
Unrealized Gains and Losses on Derivative Instruments [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance		(215)		(12)		(136)	(6)
OCI before reclassifications		25		36		(66)	25
Amounts reclassified from AOCI		16		(4)		28	1
Net current period Other comprehensive income/(loss)		41		32		(38)	26
Ending Balance		(174)		20		(174)	20
Defined Benefit Pension Plans and Other Postretirement Benefits [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance		(13,558)		(9,032)		(13,812)	(10,030)
OCI before reclassifications		31		2		31	622
Amounts reclassified from AOCI		276	[2]	168	[2]	530	546
Net current period Other comprehensive income/(loss)		307		170		561	1,168
Ending Balance		$ (13,251)		$ (8,862)		$ (13,251)	$ (8,862)

[1] Net of tax.

[2] Primarily relates to amortization of actuarial gains/losses, settlements, and curtailments for the six and three months ended June 30, 2014 totaling $535 and $163 (net of tax of $(298) and $(91)) and to amortization of actuarial gains/losses for the six and three months ended June 30, 2015 totaling $511 and $267 (net of tax of $(284) and $(147)). These are included in the net periodic pension cost of which a portion is allocated to production as inventoried costs. See Note 12.