Accumulated Other Comprehensive Income/(Loss) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Accumulated Other Comprehensive Income (Loss) [Abstract]
Total AOCI ending balance at September 30	$ (6,759)		$ (6,759)		$ (7,013)
Derivative instruments [Abstract]
Cash Flow Hedge Gain (Loss) to be Reclassified within Twelve Months	97
Parent Company [Member]
Accumulated Other Comprehensive Income (Loss) [Abstract]
Total AOCI ending balance at September 30	(6,759)	$ (6,046)	(6,759)	$ (6,046)
Foreign currency transaction [Abstract]
Beginning balance	(4,266)	(3,691)	(4,593)	(3,570)
Gains/(Losses) on foreign currency translation	25	(183)	175	(271)
Less: Tax/(Tax benefit)	(94)	0	(271)	0
Net gains/(losses) on foreign currency translation	119	(183)	446	(271)
(Gains)/Losses reclassified from AOCI to income	(17)	0	(17)	(33)
Other comprehensive income/(loss), net of tax	102	(183)	429	(304)
Ending balance	(4,164)	(3,874)	(4,164)	(3,874)
Marketable securities [Abstract]
Beginning balance	(11)	0	(14)	(6)
Gains/(Losses) on available for sale securities	(3)	0	0	11
Less: Tax/(Tax benefit)	(3)	0	2	0
Net gains/(losses) on available for sale securities	0	0	(2)	11
(Gains)/Losses reclassified from AOCI to net income	0	0	5	(1)
Less: Tax/(Tax benefit)	1	0	1	4
Net (gains)/losses reclassified from AOCI to net income	(1)	0	4	(5)
Other comprehensive income/(loss), net of tax	(1)	0	2	6
Ending balance	(12)	0	(12)	0
Derivative instruments [Abstract]
Beginning balance	253	421	283	64
Gains/(Losses) on available for sale securities	(116)	340	90	887
Less: Tax/(Tax benefit)	(36)	87	15	181
Net gains/(losses) on available for sale securities	(80)	253	75	706
(Gains)/Losses reclassified from AOCI to net income	(115)	(202)	(357)	(335)
Less: Tax/(Tax benefit)	(24)	(48)	(81)	(85)
Net (gains)/losses reclassified from AOCI to net income	(91)	(154)	(276)	(250)
Other comprehensive income/(loss), net of tax	(171)	99	(201)	456
Ending balance	82	520	82	520
Pension and other postretirement benefits
Beginning balance	(2,692)	(2,706)	(2,689)	(2,745)
Amortization of prior service costs/(credits)	15	17	45	50
Less: Tax/(Tax benefit)	(13)	7	15	17
Net prior service costs/(credits) reclassified from AOCI to net income	28	10	30	33
Translation impact on non-U.S. plans	(1)	4	(6)	20
Other comprehensive income/(loss), net of tax	27	14	24	53
Ending balance	$ (2,665)	$ (2,692)	$ (2,665)	$ (2,692)