PENSION PLANS AND OTHER POSTRETIREMENT BENEFITS (Change in Projected Benefit Obligations, Plan Assets and Funded Status of All Significant Plans) (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2021	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Defined Benefit Plan, Change in Benefit Obligations [Roll Forward]
Actuarial changes in assumptions and experience	$ (1,268)
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	26,400	$ 26,400
Fair value of plan assets at end of year		28,200	$ 26,400
Defined Benefit Pension Plans
Defined Benefit Plan, Change in Benefit Obligations [Roll Forward]
Benefit obligations at beginning of year	35,309	35,309	32,621
Service cost		387	399	$ 396
Interest cost		594	767	921
Plan participants' contributions		10	12
Actuarial changes in assumptions and experience		(820)	3,021
Benefits paid		(1,582)	(1,569)
Plan amendments		2	8
Defined Benefit Plan Business Combinations And Acquisitions Divestiture Other Benefit Obligation		8	(692)
Effect of foreign exchange rates		(545)	791
Termination Benefits/curtailment cost/settlements		(386)	(49)
Benefit obligations at end of year		32,977	35,309	32,621
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	26,406	26,406	24,908
Actual return on plan assets		2,501	2,877
Employer contributions		1,219	299
Plan participants' contributions		10	12
Benefits paid		(1,582)	(1,569)
Defined Benefit Plan, Plan Assets, Increase (Decrease) for Assets Transferred to (from) Plan		10	(681)
Effect of foreign exchange rates		(397)	571
Defined Benefit Plan, Plan Assets, Payment for Settlement		0	(11)
Fair value of plan assets at end of year		28,167	26,406	24,908
Defined Benefit Plan, Funded Status [Abstract]
Defined Benefit Plan, Funded (Unfunded) Status of Plan		(4,810)	(8,903)
Defined Benefit Plan, Amounts for Asset (Liability) Recognized in Statement of Financial Position [Abstract]
Assets for Plan Benefits, Defined Benefit Plan		1,173	1,007
Accrued and other current liabilities		(58)	(54)
Pension and other postretirement benefits - noncurrent		(5,925)	(9,856)
Defined Benefit Plan, Amounts for Asset (Liability) Recognized in Statement of Financial Position		(4,810)	(8,903)
Defined Benefit Plan, Accumulated Other Comprehensive (Income) Loss, before Tax [Abstract]
Net loss (gain)		9,934	12,736
Prior service credit		(112)	(154)
Pretax balance in AOCL at end of year		9,822	12,582
Other Postretirement Benefit Plans
Defined Benefit Plan, Change in Benefit Obligations [Roll Forward]
Benefit obligations at beginning of year	1,464	1,464	1,535
Service cost		7	7	8
Interest cost		23	40	49
Plan participants' contributions		0	0
Actuarial changes in assumptions and experience		(98)	7
Benefits paid		(141)	(132)
Plan amendments		0	0
Defined Benefit Plan Business Combinations And Acquisitions Divestiture Other Benefit Obligation		0	0
Effect of foreign exchange rates		(4)	7
Termination Benefits/curtailment cost/settlements		0	0
Benefit obligations at end of year		1,251	1,464	1,535
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	$ 0	0	0
Actual return on plan assets		0	0
Employer contributions		0	0
Plan participants' contributions		0	0
Benefits paid		0	0
Defined Benefit Plan, Plan Assets, Increase (Decrease) for Assets Transferred to (from) Plan		0	0
Effect of foreign exchange rates		0	0
Defined Benefit Plan, Plan Assets, Payment for Settlement		0	0
Fair value of plan assets at end of year		0	0	$ 0
Defined Benefit Plan, Funded Status [Abstract]
Defined Benefit Plan, Funded (Unfunded) Status of Plan		(1,251)	(1,464)
Defined Benefit Plan, Amounts for Asset (Liability) Recognized in Statement of Financial Position [Abstract]
Assets for Plan Benefits, Defined Benefit Plan		0	0
Accrued and other current liabilities		(99)	(113)
Pension and other postretirement benefits - noncurrent		(1,152)	(1,351)
Defined Benefit Plan, Amounts for Asset (Liability) Recognized in Statement of Financial Position		(1,251)	(1,464)
Defined Benefit Plan, Accumulated Other Comprehensive (Income) Loss, before Tax [Abstract]
Net loss (gain)		(221)	(129)
Prior service credit		0	0
Pretax balance in AOCL at end of year		(221)	(129)
UNITED STATES
Defined Benefit Plan, Funded Status [Abstract]
Defined Benefit Plan, Funded (Unfunded) Status of Plan		(2,585)	(5,873)
Non-US [Member]
Defined Benefit Plan, Funded Status [Abstract]
Defined Benefit Plan, Funded (Unfunded) Status of Plan		(1,467)	(2,222)
Pension Plan, Excluding Plans with Plan Assets
Defined Benefit Plan, Funded Status [Abstract]
Defined Benefit Plan, Funded (Unfunded) Status of Plan		(758)	(808)
Other Postretirement Benefit Plans, Excluding Plans with Plan Assets
Defined Benefit Plan, Funded Status [Abstract]
Defined Benefit Plan, Funded (Unfunded) Status of Plan		$ (1,251)	$ (1,464)