RESTATEMENT OF PREVIOUSLY ISSUED CONSOLIDATED FINANCIAL STATEMENTS - Consolidated Statement of Changes in Equity (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019	Dec. 31, 2018
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Beginning of period (in shares)	683,494,944
Beginning of period	$ 7,912	$ 7,866
Treasury stock, shares (in shares)	175,106,170		177,340,358
Adoption of new accounting standards	$ (4)
Net income	333	342
Other comprehensive (loss) income	(467)	$ (98)
Purchases of treasury stock (in shares)		8,100,000
Purchases of treasury stock		$ (586)
Stock issued under employee benefit plans and other	67	166
Dividends declared on common stock	$ (111)	(98)
Change in noncontrolling interests		1
End of period (in shares)	683,494,944
End of period	$ 7,730	$ 7,593
Common stock
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Beginning of period (in shares)	683,000,000	683,000,000
Beginning of period	$ 683	$ 683
End of period (in shares)	683,000,000	683,000,000
End of period	$ 683	$ 683
Common stock in treasury
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Beginning of period	$ (10,764)	$ (9,989)
Treasury stock, shares (in shares)	175,000,000	173,000,000	177,000,000	170,000,000
Purchases of treasury stock (in shares)		8,000,000
Purchases of treasury stock		$ (586)
Stock issued under employee benefit plans and other (in shares)	(2,000,000)	(5,000,000)
Stock issued under employee benefit plans and other	$ 87	$ 291
End of period	(10,677)	(10,284)
Additional contributed capital
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Beginning of period	5,955	5,898
Stock issued under employee benefit plans and other	(20)	(59)
End of period	5,935	5,839
Retained earnings
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Beginning of period	15,718	15,075
Adoption of new accounting standards	(4)	161
Net income	332	342
Stock issued under employee benefit plans and other		(66)
Dividends declared on common stock	(111)	(98)
End of period	15,935	15,414
Accumulated other comprehensive income (loss)
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Beginning of period	(3,710)	(3,823)
Adoption of new accounting standards		(161)
Other comprehensive (loss) income	(467)	(98)
End of period	(4,177)	(4,082)
Total Baxter stockholders' equity
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Beginning of period	7,882	7,844
Adoption of new accounting standards	(4)
Net income	332	342
Other comprehensive (loss) income	(467)	(98)
Purchases of treasury stock		(586)
Stock issued under employee benefit plans and other	67	166
Dividends declared on common stock	(111)	(98)
End of period	7,699	7,570
Noncontrolling interests
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Beginning of period	30	22
Net income	1
Change in noncontrolling interests		1
End of period	$ 31	23
As previously reported
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Beginning of period		7,816
Net income		347
Other comprehensive (loss) income		23
Purchases of treasury stock		(586)
Stock issued under employee benefit plans and other		166
Dividends declared on common stock		(98)
Change in noncontrolling interests		1
End of period		$ 7,669
As previously reported | Common stock
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Beginning of period (in shares)		683,000,000
Beginning of period		$ 683
End of period (in shares)		683,000,000
End of period		$ 683
As previously reported | Common stock in treasury
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Beginning of period		$ (9,989)
Treasury stock, shares (in shares)		173,000,000		170,000,000
Purchases of treasury stock (in shares)		8,000,000
Purchases of treasury stock		$ (586)
Stock issued under employee benefit plans and other (in shares)		(5,000,000)
Stock issued under employee benefit plans and other		$ 291
End of period		(10,284)
As previously reported | Additional contributed capital
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Beginning of period		5,898
Stock issued under employee benefit plans and other		(59)
End of period		5,839
As previously reported | Retained earnings
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Beginning of period		15,626
Net income		347
Stock issued under employee benefit plans and other		(66)
Dividends declared on common stock		(98)
End of period		15,970
As previously reported | Accumulated other comprehensive income (loss)
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Beginning of period		(4,424)
Other comprehensive (loss) income		23
End of period		(4,562)
As previously reported | Total Baxter stockholders' equity
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Beginning of period		7,794
Net income		347
Other comprehensive (loss) income		23
Purchases of treasury stock		(586)
Stock issued under employee benefit plans and other		166
Dividends declared on common stock		(98)
End of period		7,646
As previously reported | Noncontrolling interests
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Beginning of period		22
Change in noncontrolling interests		1
End of period		23
Restatement impacts
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Beginning of period		50
Net income		(5)
Other comprehensive (loss) income		(121)
End of period		$ (76)
Restatement impacts | Common stock
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Beginning of period (in shares)		0
Beginning of period		$ 0
End of period (in shares)		0
End of period		$ 0
Restatement impacts | Common stock in treasury
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Beginning of period		$ 0
Treasury stock, shares (in shares)		0		0
End of period		$ 0
Restatement impacts | Additional contributed capital
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Beginning of period		0
End of period		0
Restatement impacts | Retained earnings
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Beginning of period		(551)
Net income		(5)
End of period		(556)
Restatement impacts | Accumulated other comprehensive income (loss)
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Beginning of period		601
Other comprehensive (loss) income		(121)
End of period		480
Restatement impacts | Total Baxter stockholders' equity
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Beginning of period		50
Net income		(5)
Other comprehensive (loss) income		(121)
End of period		(76)
Restatement impacts | Noncontrolling interests
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Beginning of period		0
End of period		$ 0