Accumulated Other Comprehensive Income/(Loss) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Derivative instruments [Abstract]
Cash Flow Hedge Gain (Loss) to be Reclassified within Twelve Months	$ 147
Pension and other postretirement benefits
Total AOCI ending balance at March 31	(8,461)		$ (7,728)
Parent Company [Member]
Foreign currency transaction [Abstract]
Beginning balance	(4,626)	$ (4,800)
Gains/(Losses) on foreign currency translation	(1,406)	271
Less: Tax/(Tax benefit)	27	28
Net gains/(losses) on foreign currency translation	(1,433)	243
(Gains)/Losses reclassified from AOCI to income	(20)	0
Other comprehensive income/(loss), net of tax	(1,453)	243
Ending balance	(6,079)	(4,557)
Marketable securities [Abstract]
Beginning balance	71	(59)
Gains/(Losses) on available for sale securities	19	80
Less: Tax/(Tax benefit)	5	19
Net gains/(losses) on available for sale securities	14	61
(Gains)/Losses reclassified from AOCI to net income	0	3
Less: Tax/(Tax benefit)	0	1
Net (gains)/losses reclassified from AOCI to net income	0	2
Other comprehensive income/(loss), net of tax	14	63
Ending balance	85	4
Derivative instruments [Abstract]
Beginning balance	(488)	201
Gains/(Losses) on available for sale securities	796	(510)
Less: Tax/(Tax benefit)	173	(102)
Net gains/(losses) on available for sale securities	623	(408)
(Gains)/Losses reclassified from AOCI to net income	84	(49)
Less: Tax/(Tax benefit)	15	(11)
Net (gains)/losses reclassified from AOCI to net income	69	(38)
Other comprehensive income/(loss), net of tax	692	(446)
Ending balance	204	(245)
Pension and other postretirement benefits
Beginning balance	(2,685)	(2,708)
Amortization of prior service costs/(credits)	4	12
Less: Tax/(Tax benefit)	1	2
Net prior service costs/(credits) reclassified from AOCI to net income	3	10
Translation impact on non-U.S. plans	11	(5)
Other comprehensive income/(loss), net of tax	14	5
Ending balance	(2,671)	(2,703)
Total AOCI ending balance at March 31	$ (8,461)	$ (7,501)