EARNINGS PER SHARE - Reconciliation of Basic Shares to Diluted Shares (Details) - USD ($) shares in Millions, $ in Millions	3 Months Ended								6 Months Ended		12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Weighted Average Number of Shares Outstanding Reconciliation [Abstract]
Income from continuing operations			$ 313	$ 342	$ 311		$ 341	$ 382	$ 655	$ 723	$ 1,011	$ 1,552	$ 609
Less: Income from continuing operations attributable to noncontrolling interests					311	$ 518	341	382			1,001	1,552	609
Loss from discontinued operations, net of tax					(6)	0	0	0		0	0	(6)	(7)
Less: Net income attributable to noncontrolling interests											10	0	0
Net income attributable to Baxter stockholders	$ (23)	$ 369	$ 313	$ 342	$ 305	$ 518	$ 341	$ 382	$ 655	$ 723	$ 1,001	$ 1,546	$ 602
Basic (in shares)			510	512	528		535	539	511	537	509	534	543
Effect of dilutive securities											10	12	12
Diluted (in shares)			519	522	538		547	551	520	549	519	546	555