SHAREHOLDERS' EQUITY - Schedule of Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax
Beginning balance			$ 29,861
Other comprehensive income (loss)	$ 627	$ 547	1,545	$ 1,577
Ending balance	35,254	56,129	35,254	56,129
Adjustments to investment securities before reclassifications	(2,229)	(1,054)	(962)	(2,011)
Accumulated other comprehensive income (loss)
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax
Beginning balance	(10,819)	(13,485)	(11,732)	(14,414)
Ending balance	(10,194)	(12,852)	(10,194)	(12,852)
Investment securities including noncontrolling interests
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax
Beginning balance	20	(16)	61	(39)
Other comprehensive income (loss) before reclassifications	34	94	41	121
Other comprehensive income (loss) before reclassifications, deferred taxes	8	(23)	7	15
Reclassifications from other comprehensive income	(7)	(18)	(55)	(22)
Reclassifications from other comprehensive income, deferred taxes	(2)	(5)	(14)	(6)
Other comprehensive income (loss)	27	76	(14)	99
Investment securities attributable to noncontrolling interests
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax
Other comprehensive income (loss)	0	0	0	1
Investment securities
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax
Other comprehensive income (loss)	27	75	(14)	98
Ending balance	47		47
Currency translation adjustments including noncontrolling interests
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax
Beginning balance	(4,685)	(5,810)	(4,818)	(6,134)
Other comprehensive income (loss) before reclassifications	(58)	(308)	(613)	(1)
Other comprehensive income (loss) before reclassifications, deferred taxes	25	13	20	39
Reclassifications from other comprehensive income	1	167	691	284
Reclassifications from other comprehensive income, deferred taxes	0	0	0	(4)
Other comprehensive income (loss)	(57)	(141)	78	283
Currency translation adjustments attributable to noncontrolling interests
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax
Other comprehensive income (loss)	1	(77)	3	22
Currency translation adjustments
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax
Other comprehensive income (loss)	(58)	(64)	75	260
Ending balance	(4,743)	(5,874)	(4,743)	(5,874)
Cash flow hedges including noncontrolling interests
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax
Beginning balance	(163)	49	49	13
Other comprehensive income (loss) before reclassifications	40	(50)	(222)	(16)
Other comprehensive income (loss) before reclassifications, deferred taxes	(24)	(8)	(69)	3
Reclassifications from other comprehensive income	13	25	64	28
Reclassifications from other comprehensive income, deferred taxes	(1)	4	8	1
Other comprehensive income (loss)	53	(25)	(158)	12
Cash flow hedges attributable to noncontrolling interests
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax
Other comprehensive income (loss)	0	(1)	0	1
Cash flow hedges
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax
Other comprehensive income (loss)	53	(23)	(158)	12
Ending balance	(109)	26	(109)	26
Benefit plans including noncontrolling interests
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax
Beginning balance	(5,991)	(7,708)	(7,024)	(8,254)
Other comprehensive income (loss) before reclassifications	(74)	7	145	(111)
Other comprehensive income (loss) before reclassifications, deferred taxes	(2)	13	28	(35)
Reclassifications from other comprehensive income	678	632	1,495	1,294
Reclassifications from other comprehensive income, deferred taxes	187	164	426	347
Other comprehensive income (loss)	604	639	1,640	1,183
Benefit plans attributable to noncontrolling interests
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax
Other comprehensive income (loss)	0	(6)	3	(8)
Benefit plans
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax
Other comprehensive income (loss)	604	645	1,636	1,192
Ending balance	$ (5,387)	$ (7,063)	(5,387)	$ (7,063)
BioPharma | Benefit plans including noncontrolling interests
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax
Reclassifications from other comprehensive income			(836)
Currency translation, net of taxes			$ 688