RETIREMENT BENEFITS - Funded Status and Accumulated Other Comprehensive Income (Details) - USD ($) $ in Millions	3 Months Ended				9 Months Ended
	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
U.S. Pension Plans
Change in projected benefit obligation (PBO)
Projected benefit obligation at beginning of year			$ 13,943		$ 13,943
Projected benefit obligation at period end—Significant Plans	$ 14,817				14,817
Change in plan assets
Plan assets at fair value at beginning of year			12,137		12,137
Plan assets at fair value at period end—Significant Plans	12,687				12,687
Funded status of the Significant plans	(2,130)				(2,130)
Net amount recognized
Benefit asset	0				0
Benefit liability	(2,130)				(2,130)
Net amount recognized on the balance sheet—Significant Plans	(2,130)				(2,130)
Amounts recognized in AOCI
Prior service benefit	0				0
Net actuarial gain (loss)	(7,341)				(7,341)
Net amount recognized in equity-pretax	(7,341)				(7,341)
Accumulated benefit obligation at period end—Significant Plans	14,810				14,810
U.S. Pension Plans | Other than Significant Plans Measured Annually
Change in projected benefit obligation (PBO)
Projected benefit obligation at beginning of year			0		0
Change in plan assets
Plan assets at fair value at beginning of year			0		0
U.S. Pension Plans | Significant Plans Measured Quarterly
Change in projected benefit obligation (PBO)
Projected benefit obligation at beginning of year	14,912		13,943		13,943
First quarter activity/Second quarter activity		$ 395	574
Benefits earned during the period	1
Interest cost on benefit obligation	132
Actuarial loss (gain)	76
Benefits paid, net of participants’ contributions	(191)
Curtailment loss	10
Foreign exchange impact and other	(123)
Projected benefit obligation at period end—Significant Plans		14,912
Change in plan assets
Plan assets at fair value at beginning of year	12,255		12,137		12,137
First quarter activity/second quarter activity		190	(72)
Actual return on plan assets	235
Company contributions, net of reimbursements	513
Plan participants’ contributions	0
Benefits paid, net of government subsidy	(191)
Foreign exchange impact and other	(125)
Plan assets at fair value at period end—Significant Plans		12,255
U.S. Qualified Pension Plan
Change in projected benefit obligation (PBO)
Benefits earned during the period	1			$ 1	2	$ 3
Interest cost on benefit obligation	126			143	399	411
Change in plan assets
Funded status of the Significant plans	(1,387)				(1,387)
U.S. Nonqualified Pension Plan
Change in plan assets
Funded status of the Significant plans	(743)				(743)
Non-U.S. Pension Plans
Change in projected benefit obligation (PBO)
Projected benefit obligation at beginning of year			6,534		6,534
Projected benefit obligation at period end—Significant Plans	5,264				5,264
Change in plan assets
Plan assets at fair value at beginning of year			6,104		6,104
Plan assets at fair value at period end—Significant Plans	5,413				5,413
Funded status of the Significant plans	150				150
Net amount recognized
Benefit asset	728				728
Benefit liability	(578)				(578)
Net amount recognized on the balance sheet—Significant Plans	150				150
Amounts recognized in AOCI
Prior service benefit	38				38
Net actuarial gain (loss)	(991)				(991)
Net amount recognized in equity-pretax	(953)				(953)
Accumulated benefit obligation at period end—Significant Plans	4,935				4,935
Non-U.S. Pension Plans | Other than Significant Plans Measured Annually
Change in projected benefit obligation (PBO)
Projected benefit obligation at beginning of year			1,819		1,819
Change in plan assets
Plan assets at fair value at beginning of year			1,175		1,175
Non-U.S. Pension Plans | Significant Plans Measured Quarterly
Change in projected benefit obligation (PBO)
Projected benefit obligation at beginning of year	5,008		4,715		4,715
First quarter activity/Second quarter activity		94	199
Benefits earned during the period	25
Interest cost on benefit obligation	57
Actuarial loss (gain)	354
Benefits paid, net of participants’ contributions	(76)
Curtailment loss	0
Foreign exchange impact and other	(104)
Projected benefit obligation at period end—Significant Plans		5,008
Change in plan assets
Plan assets at fair value at beginning of year	5,263		4,929		4,929
First quarter activity/second quarter activity		101	233
Actual return on plan assets	370
Company contributions, net of reimbursements	12
Plan participants’ contributions	1
Benefits paid, net of government subsidy	(76)
Foreign exchange impact and other	(157)
Plan assets at fair value at period end—Significant Plans		5,263
Non-U.S. Qualified Pension Plan
Change in projected benefit obligation (PBO)
Benefits earned during the period	39			42	116	129
Interest cost on benefit obligation	70			77	216	237
Change in plan assets
Funded status of the Significant plans	150				150
Non-U.S. Nonqualified Pension Plan
Change in plan assets
Funded status of the Significant plans	0				0
U.S. Postretirement Benefit Plans
Change in projected benefit obligation (PBO)
Projected benefit obligation at beginning of year			817		817
Projected benefit obligation at period end—Significant Plans	729				729
Change in plan assets
Plan assets at fair value at beginning of year			166		166
Plan assets at fair value at period end—Significant Plans	138				138
Funded status of the Significant plans	(591)				(591)
Net amount recognized
Benefit asset	0				0
Benefit liability	(591)				(591)
Net amount recognized on the balance sheet—Significant Plans	(591)				(591)
Amounts recognized in AOCI
Prior service benefit	0				0
Net actuarial gain (loss)	70				70
Net amount recognized in equity-pretax	70				70
Accumulated benefit obligation at period end—Significant Plans	729				729
U.S. Postretirement Benefit Plans | Other than Significant Plans Measured Annually
Change in projected benefit obligation (PBO)
Projected benefit obligation at beginning of year			0		0
Change in plan assets
Plan assets at fair value at beginning of year			0		0
U.S. Postretirement Benefit Plans | Significant Plans Measured Quarterly
Change in projected benefit obligation (PBO)
Projected benefit obligation at beginning of year	733		817		817
First quarter activity/Second quarter activity		(106)	22
Benefits earned during the period	0
Interest cost on benefit obligation	6
Actuarial loss (gain)	(2)
Benefits paid, net of participants’ contributions	(8)
Curtailment loss	0
Foreign exchange impact and other	0
Projected benefit obligation at period end—Significant Plans		733
Change in plan assets
Plan assets at fair value at beginning of year	145		166		166
First quarter activity/second quarter activity		(21)	0
Actual return on plan assets	8
Company contributions, net of reimbursements	(7)
Plan participants’ contributions	0
Benefits paid, net of government subsidy	(8)
Foreign exchange impact and other	0
Plan assets at fair value at period end—Significant Plans		145
U.S. Qualified Postretirement Benefit Plan
Change in projected benefit obligation (PBO)
Benefits earned during the period	0			0	0	0
Interest cost on benefit obligation	6			8	19	24
Change in plan assets
Funded status of the Significant plans	(591)				(591)
U.S. Nonqualified Postretirement Benefit Plan
Change in plan assets
Funded status of the Significant plans	0				0
Non-U.S. Postretirement Benefit Plans
Change in projected benefit obligation (PBO)
Projected benefit obligation at beginning of year			1,291		1,291
Projected benefit obligation at period end—Significant Plans	964				964
Change in plan assets
Plan assets at fair value at beginning of year			1,133		1,133
Plan assets at fair value at period end—Significant Plans	1,104				1,104
Funded status of the Significant plans	140				140
Net amount recognized
Benefit asset	140				140
Benefit liability	0				0
Net amount recognized on the balance sheet—Significant Plans	140				140
Amounts recognized in AOCI
Prior service benefit	93				93
Net actuarial gain (loss)	(383)				(383)
Net amount recognized in equity-pretax	(290)				(290)
Accumulated benefit obligation at period end—Significant Plans	964				964
Non-U.S. Postretirement Benefit Plans | Other than Significant Plans Measured Annually
Change in projected benefit obligation (PBO)
Projected benefit obligation at beginning of year			282		282
Change in plan assets
Plan assets at fair value at beginning of year			8		8
Non-U.S. Postretirement Benefit Plans | Significant Plans Measured Quarterly
Change in projected benefit obligation (PBO)
Projected benefit obligation at beginning of year	1,007		1,009		1,009
First quarter activity/Second quarter activity		(32)	30
Benefits earned during the period	2
Interest cost on benefit obligation	20
Actuarial loss (gain)	(6)
Benefits paid, net of participants’ contributions	(12)
Curtailment loss	0
Foreign exchange impact and other	(47)
Projected benefit obligation at period end—Significant Plans		1,007
Change in plan assets
Plan assets at fair value at beginning of year	1,108		1,125		1,125
First quarter activity/second quarter activity		(56)	$ 39
Actual return on plan assets	61
Company contributions, net of reimbursements	0
Plan participants’ contributions	0
Benefits paid, net of government subsidy	(12)
Foreign exchange impact and other	(53)
Plan assets at fair value at period end—Significant Plans		$ 1,108
Non-U.S. Qualified Postretirement Benefit Plan
Change in projected benefit obligation (PBO)
Benefits earned during the period	1			3	7	10
Interest cost on benefit obligation	24			$ 25	72	$ 82
Change in plan assets
Funded status of the Significant plans	140				140
Non-U.S. Nonqualified Postretirement Benefit Plan
Change in plan assets
Funded status of the Significant plans	$ 0				$ 0