SHAREOWNERS' EQUITY - Schedule of Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax
Beginning balance			$ 77,491
Reclassifications from OCI – net of deferred taxes	$ 254	$ 602	1,779	$ 1,548
Other comprehensive income (loss)	1,058	481	4,209	2,117
Less OCI attributable to noncontrolling interests	127	5	134	10
Accumulated other comprehensive income (loss) at September 30	94,052	83,544	94,052	83,544
Investment securities
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax
Beginning balance	866	1,077	674	460
Other comprehensive income (loss) (OCI) before reclassifications – net of deferred taxes	54	97	363	675
Reclassifications from OCI – net of deferred taxes	(32)	1	(150)	40
Other comprehensive income (loss)	21	97	213	715
Less OCI attributable to noncontrolling interests	1	(2)	1	(1)
Accumulated other comprehensive income (loss) at September 30	887	1,176	887	1,176
Deferred taxes, other comprehensive income (loss) (OCI) before reclassifications	45	48	204	352
Deferred taxes, reclassifications from OCI	(17)	5	(78)	36
Currency translation adjustments (CTA)
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax
Beginning balance	(5,481)	(5,448)	(6,816)	(5,499)
Other comprehensive income (loss) (OCI) before reclassifications – net of deferred taxes	710	(280)	1,463	(138)
Reclassifications from OCI – net of deferred taxes	(196)	85	391	1
Other comprehensive income (loss)	513	(194)	1,854	(138)
Less OCI attributable to noncontrolling interests	125	0	131	6
Accumulated other comprehensive income (loss) at September 30	(5,092)	(5,643)	(5,092)	(5,643)
Deferred taxes, other comprehensive income (loss) (OCI) before reclassifications	(407)	5	(648)	222
Deferred taxes, reclassifications from OCI	2	(6)	(538)	74
Cash flow hedges
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax
Beginning balance	22	(51)	12	(80)
Other comprehensive income (loss) (OCI) before reclassifications – net of deferred taxes	175	(21)	239	(61)
Reclassifications from OCI – net of deferred taxes	(75)	52	(129)	121
Other comprehensive income (loss)	100	30	109	60
Less OCI attributable to noncontrolling interests	3	0	3	0
Accumulated other comprehensive income (loss) at September 30	119	(21)	119	(21)
Deferred taxes, other comprehensive income (loss) (OCI) before reclassifications	55	(12)	53	(17)
Deferred taxes, reclassifications from OCI	(28)	6	(37)	7
Benefit plans
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax
Beginning balance	(10,860)	(10,476)	(12,469)	(11,410)
Reclassifications from OCI – net of deferred taxes	557	465	1,667	1,387
Other comprehensive income (loss)	423	548	2,032	1,481
Less OCI attributable to noncontrolling interests	(1)	6	(1)	5
Accumulated other comprehensive income (loss) at September 30	(10,436)	(9,934)	(10,436)	(9,934)
Deferred taxes, reclassifications from OCI	275	238	833	712
Prior service credit (costs)/Prior service cost amortization - net of deferred taxes
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax
Other comprehensive income (loss) (OCI) before reclassifications – net of deferred taxes	0	0	0	23
Reclassifications from OCI – net of deferred taxes	13	12	34	45
Deferred taxes, other comprehensive income (loss) (OCI) before reclassifications	0	0	0	5
Deferred taxes, reclassifications from OCI	17	22	55	63
Net actuarial gain (loss)/Net actuarial loss amortization – net of deferred taxes
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax
Other comprehensive income (loss) (OCI) before reclassifications – net of deferred taxes	(132)	83	367	71
Reclassifications from OCI – net of deferred taxes	536	453	1,595	1,343
Deferred taxes, other comprehensive income (loss) (OCI) before reclassifications	(49)	49	84	6
Deferred taxes, reclassifications from OCI	255	216	759	649
Net curtailment/settlement - net of deferred taxes of $X, $0, $X and $0
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax
Other comprehensive income (loss) (OCI) before reclassifications – net of deferred taxes	8	0	38	(1)
Deferred taxes, other comprehensive income (loss) (OCI) before reclassifications	3	0	19	0
Accumulated other comprehensive income (loss)
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax
Accumulated other comprehensive income (loss) at September 30	$ (14,523)	$ (14,422)	$ (14,523)	$ (14,422)

Amount after tax, before reclassification adjustments of other comprehensive income (loss).

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