Accumulated Other Comprehensive Income/(Loss) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Accumulated Other Comprehensive Income/(Loss) [Line Items]
Accumulated other comprehensive income/(loss) (Note 23)	$ (7,728)	$ (7,366)
Pension and other postretirement benefits
Cash Flow Hedge Gain (Loss) to be Reclassified within Twelve Months	(344)
Parent Company [Member]
Accumulated Other Comprehensive Income/(Loss) [Line Items]
Accumulated other comprehensive income/(loss) (Note 23)	(7,728)	(7,366)	$ (6,959)
Foreign currency translation
Beginning balance	(4,800)	(4,277)	(4,593)
Gains/(Losses) on foreign currency translation	181	(435)	38
Less: Tax/(Tax benefit) (a)	6	91	(294)
Net gains/(losses) on foreign currency translation	175	(526)	332
(Gains)/Losses reclassified from AOCI to net income (b)	(1)	3	(16)
Other comprehensive income/(loss), net of tax	174	(523)	316
Ending balance	(4,626)	(4,800)	(4,277)
Marketable securities
Beginning balance	(59)	(48)	(14)
Gains/(Losses) on available for sale securities	173	(37)	(53)
Less: Tax/(Tax benefit)	40	(8)	(15)
Net gains/(losses) on available for sale securities	133	(29)	(38)
(Gains)/Losses reclassified from AOCI to net income	(3)	20	5
Less: Tax/(Tax benefit)	0	2	1
Net (gains)/losses reclassified from AOCI to net income	(3)	18	4
Other comprehensive income/(loss), net of tax	130	(11)	(34)
Ending balance	71	(59)	(48)
Derivative instruments
Beginning balance	201	18	283
Gains/(Losses) on derivative instruments	(875)	288	134
Less: Tax/(Tax benefit)	(180)	65	80
Net gains/(losses) on derivative instruments	(695)	223	54
(Gains)/Losses reclassified from AOCI to net income	3	(50)	(456)
Less: Tax/(Tax benefit)	(3)	(10)	(137)
Net (gains)/losses reclassified from AOCI to net income (c)	6	(40)	(319)
Other comprehensive income/(loss), net of tax	(689)	183	(265)
Ending balance	(488)	201	18
Pension and other postretirement benefits
Beginning balance	(2,708)	(2,652)	(2,689)
Prior service (costs)/credits arising during the period	(15)	(135)	5
Less: Tax/(Tax benefit)	(2)	(23)	0
Net prior service (costs)/credits arising during the period	(13)	(112)	5
Amortization and recognition of prior service costs/(credits) (d)	50	59	60
Less: Tax/(Tax benefit)	10	13	20
Net prior service costs/(credits) reclassified from AOCI to net income	40	46	40
Translation impact on non-U.S. plans	(4)	10	(8)
Other comprehensive income/(loss), net of tax	23	(56)	37
Ending balance	$ (2,685)	$ (2,708)	$ (2,652)