Accumulated Other Comprehensive Income/(Loss) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Derivative instruments [Abstract]
Cash Flow Hedge Gain (Loss) to be Reclassified within Twelve Months	$ 155
Pension and other postretirement benefits
Total AOCI ending balance at September 30	(8,613)		$ (8,613)		$ (7,728)
Parent Company [Member]
Foreign currency transaction [Abstract]
Beginning balance	(6,181)	$ (4,684)	(4,626)	$ (4,800)
Gains/(Losses) on foreign currency translation	(126)	(301)	(1,673)	(169)
Less: Tax/(Tax benefit)	(60)	58	(83)	74
Net gains/(losses) on foreign currency translation	(66)	(359)	(1,590)	(243)
(Gains)/Losses reclassified from AOCI to income	(3)	(1)	(34)	(1)
Other comprehensive income/(loss), net of tax	(69)	(360)	(1,624)	(244)
Ending balance	(6,250)	(5,044)	(6,250)	(5,044)
Marketable securities [Abstract]
Beginning balance	184	63	71	(59)
Gains/(Losses) on available for sale securities	(8)	15	157	169
Less: Tax/(Tax benefit)	(2)	4	36	40
Net gains/(losses) on available for sale securities	(6)	11	121	129
(Gains)/Losses reclassified from AOCI to net income	(15)	(3)	(33)	2
Less: Tax/(Tax benefit)	(4)	0	(8)	1
Net (gains)/losses reclassified from AOCI to net income	(11)	(3)	(25)	1
Other comprehensive income/(loss), net of tax	(17)	8	96	130
Ending balance	167	71	167	71
Derivative instruments [Abstract]
Beginning balance	180	(128)	(488)	201
Gains/(Losses) on available for sale securities	(96)	(100)	636	(442)
Less: Tax/(Tax benefit)	(15)	(17)	135	(95)
Net gains/(losses) on available for sale securities	(81)	(83)	501	(347)
(Gains)/Losses reclassified from AOCI to net income	16	18	118	(69)
Less: Tax/(Tax benefit)	6	4	22	(18)
Net (gains)/losses reclassified from AOCI to net income	10	14	96	(51)
Other comprehensive income/(loss), net of tax	(71)	(69)	597	(398)
Ending balance	109	(197)	109	(197)
Pension and other postretirement benefits
Beginning balance	(2,654)	(2,687)	(2,685)	(2,708)
Amortization of prior service costs/(credits)	29	12	55	37
Less: Tax/(Tax benefit)	6	2	10	7
Net prior service costs/(credits) reclassified from AOCI to net income	23	10	45	30
Translation impact on non-U.S. plans	(8)	5	1	6
Other comprehensive income/(loss), net of tax	15	15	46	36
Ending balance	(2,639)	(2,672)	(2,639)	(2,672)
Total AOCI ending balance at September 30	$ (8,613)	$ (7,842)	$ (8,613)	$ (7,842)