Accumulated Other Comprehensive Income/(Loss) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Derivative instruments [Abstract]
Cash Flow Hedge Gain (Loss) to be Reclassified within Twelve Months	$ (82)
Pension and other postretirement benefits
Total AOCI ending balance at June 30	(7,436)		$ (7,436)		$ (7,366)
Parent Company [Member]
Foreign currency transaction [Abstract]
Beginning balance	(4,557)	$ (3,981)	(4,800)	$ (4,277)
Gains/(Losses) on foreign currency translation	(139)	(527)	132	(283)
Less: Tax/(Tax benefit)	(12)	69	16	19
Net gains/(losses) on foreign currency translation	(127)	(596)	116	(302)
(Gains)/Losses reclassified from AOCI to income	0	0	0	2
Other comprehensive income/(loss), net of tax	(127)	(596)	116	(300)
Ending balance	(4,684)	(4,577)	(4,684)	(4,577)
Marketable securities [Abstract]
Beginning balance	4	(95)	(59)	(48)
Gains/(Losses) on available for sale securities	74	(15)	154	(84)
Less: Tax/(Tax benefit)	17	(4)	36	(21)
Net gains/(losses) on available for sale securities	57	(11)	118	(63)
(Gains)/Losses reclassified from AOCI to net income	2	4	5	10
Less: Tax/(Tax benefit)	0	1	1	2
Net (gains)/losses reclassified from AOCI to net income	2	3	4	8
Other comprehensive income/(loss), net of tax	59	(8)	122	(55)
Ending balance	63	(103)	63	(103)
Derivative instruments [Abstract]
Beginning balance	(245)	51	201	18
Gains/(Losses) on available for sale securities	168	60	(342)	121
Less: Tax/(Tax benefit)	24	14	(78)	29
Net gains/(losses) on available for sale securities	144	46	(264)	92
(Gains)/Losses reclassified from AOCI to net income	(38)	12	(87)	(5)
Less: Tax/(Tax benefit)	(11)	6	(22)	2
Net (gains)/losses reclassified from AOCI to net income	(27)	6	(65)	(7)
Other comprehensive income/(loss), net of tax	117	52	(329)	85
Ending balance	(128)	103	(128)	103
Pension and other postretirement benefits
Beginning balance	(2,703)	(2,644)	(2,708)	(2,652)
Amortization of prior service costs/(credits)	13	14	25	29
Less: Tax/(Tax benefit)	3	3	5	6
Net prior service costs/(credits) reclassified from AOCI to net income	10	11	20	23
Translation impact on non-U.S. plans	6	6	1	2
Other comprehensive income/(loss), net of tax	16	17	21	25
Ending balance	(2,687)	(2,627)	(2,687)	(2,627)
Total AOCI ending balance at June 30	$ (7,436)	$ (7,204)	$ (7,436)	$ (7,204)