ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) - Summary of Amounts Reclassification from AOCI to Net Income (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income (loss) from discontinued operations, net of tax	$ 5	$ 83	$ 36	$ (290)
Income tax expense (benefit)	(172)	(8)	(116)	(70)
Net income (loss) attributable to Baxter stockholders	(46)	140	171	(137)
Other (income) expense, net	7	1	10	34
Costs of sales	(1,885)	(1,666)	(5,468)	(4,858)
Amounts reclassified from AOCI
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net income (loss) attributable to Baxter stockholders	2	3	(107)	3
Amounts reclassified from AOCI | CTA
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income (loss) from discontinued operations, net of tax	0		(126)
Income tax expense (benefit)	0		0
Net income (loss) attributable to Baxter stockholders	0		(126)
Amounts reclassified from AOCI | Pension and OPEB items
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income (loss) from discontinued operations, net of tax	0		(14)
Income tax expense (benefit)	0	0	(2)	1
Net income (loss) attributable to Baxter stockholders	3		18
Other (income) expense, net	3	1	9	4
Income (loss), before tax	3	1	23	3
Less: Tax effect on pension settlement from Kidney Care separation	0		(3)
Amounts reclassified from AOCI | Gains (losses) on hedging activities
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income tax expense (benefit)	0	(1)	(1)	0
Net income (loss) attributable to Baxter stockholders	(1)	2	1	0
Income (loss), before tax	(1)	3	2	0
Amounts reclassified from AOCI | Gains (losses) on hedging activities | Foreign exchange contracts
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest expense, net	0		6
Costs of sales		4		9
Amounts reclassified from AOCI | Gains (losses) on hedging activities | Interest rate contracts
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest expense, net		(1)		(4)
Costs of sales	$ (1)		$ (4)
Amounts reclassified from AOCI | Gains (losses) on hedging activities | Fair value hedges
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other (income) expense, net		$ 0		$ (5)