EQUITY - Reclassifications and Taxes (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2022	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2021
Reclassifications and Taxes Related to Items of Other Comprehensive Income (Loss)
Other comprehensive income (loss)	$ 54	$ (82)	$ 27	$ 292
Accumulated Other Comprehensive Income (Loss)
Reclassifications and Taxes Related to Items of Other Comprehensive Income (Loss)
Other comprehensive income (loss), before tax amount	105	(88)	40	324
Other comprehensive income (loss), tax (expense) benefit	(50)	6	(14)	(33)
Other comprehensive income (loss)	54	(82)	27	292
Foreign Currency Translation Adjustments
Reclassifications and Taxes Related to Items of Other Comprehensive Income (Loss)
Other comprehensive income (loss), before tax amount	(51)	(47)	(186)	194
Other comprehensive income (loss)	(51)	(47)	(186)	194
Foreign Currency Translation Adjustments Excluding Net Investment Hedges
Reclassifications and Taxes Related to Items of Other Comprehensive Income (Loss)
Unrealized gains (losses) arising during the period, before tax amount		(36)
Unrealized gains (losses) arising during the period, net of tax amount		(36)
Unrealized Losses on Net Investment Hedges
Reclassifications and Taxes Related to Items of Other Comprehensive Income (Loss)
Unrealized gains (losses) arising during the period, before tax amount		(11)
Unrealized gains (losses) arising during the period, net of tax amount		(11)
Unrealized Gains (Losses) on Cash Flow Hedges
Reclassifications and Taxes Related to Items of Other Comprehensive Income (Loss)
Unrealized gains (losses) arising during the period, before tax amount	1	22	(4)	4
Unrealized gains (losses) arising during the period, tax (expense) benefit		(1)
Unrealized gains (losses) arising during the period, net of tax amount	1	21	(4)	4
Reclassification/amortization, before tax amount	(1)	(21)	2	(1)
Reclassification/amortization, net of tax amount	(1)	(21)	2	(1)
Other comprehensive income (loss), before tax amount		1	(3)	3
Other comprehensive income (loss), tax (expense) benefit		(1)
Other comprehensive income (loss)			(2)	3
Net Change Retirement-Related Benefit Plans
Reclassifications and Taxes Related to Items of Other Comprehensive Income (Loss)
Other comprehensive income (loss), before tax amount	156	(42)	229	127
Other comprehensive income (loss), tax (expense) benefit	(50)	7	(14)	(33)
Other comprehensive income (loss)	105	(36)	215	94
Retirement-Related Benefit Plans, Curtailments and Settlements
Reclassifications and Taxes Related to Items of Other Comprehensive Income (Loss)
Unrealized gains (losses) arising during the period, before tax amount	4	10	10	3
Unrealized gains (losses) arising during the period, tax (expense) benefit	(1)	(2)	(2)	(1)
Unrealized gains (losses) arising during the period, net of tax amount	3	8	8	2
Retirement-Related Benefit Plans, Prior Service Costs (Credits)
Reclassifications and Taxes Related to Items of Other Comprehensive Income (Loss)
Unrealized gains (losses) arising during the period, before tax amount		(3)	4	1
Unrealized gains (losses) arising during the period, tax (expense) benefit		1		(2)
Unrealized gains (losses) arising during the period, net of tax amount		(2)	3	(1)
Reclassification/amortization, before tax amount		1	1
Reclassification/amortization, tax (expense) benefit		0
Reclassification/amortization, net of tax amount		1	1
Retirement-Related Benefit Plans, Net Gains (Losses)
Reclassifications and Taxes Related to Items of Other Comprehensive Income (Loss)
Unrealized gains (losses) arising during the period, before tax amount	136	(56)	175	72
Unrealized gains (losses) arising during the period, tax (expense) benefit	(45)	10		(17)
Unrealized gains (losses) arising during the period, net of tax amount	91	(45)	175	54
Reclassification/amortization, before tax amount	16	5	40	51
Reclassification/amortization, tax (expense) benefit	(4)	(2)	(11)	(13)
Reclassification/amortization, net of tax amount	$ 12	$ 3	$ 29	$ 38