RESTATEMENT OF PREVIOUSLY ISSUED CONSOLIDATED FINANCIAL STATEMENTS - Consolidated Statement of Changes in Equity (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2017
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Beginning of period (in shares)			683,494,944
Beginning of period	$ 7,803	$ 8,830	$ 7,866	$ 9,109	$ 9,109
Treasury stock, shares (in shares)	175,461,299		175,461,299		170,495,859
Adoption of new accounting standards			$ 0	(23)
Net income	$ 369	518	1,024	1,241
Other comprehensive income (loss)	(202)	2	$ (304)	$ (212)
Purchases of treasury stock (in shares)			13,500,000	14,900,000
Purchases of treasury stock	(346)	(247)	$ (1,043)	$ (1,028)
Stock issued under employee benefit plans and other	105	94	394	302
Dividends declared on common stock	(117)	(102)	(327)	(290)
Change in noncontrolling interests	$ (1)	(5)	$ 1	(9)
End of period (in shares)	683,494,944		683,494,944		683,494,944
End of period	$ 7,617	9,090	$ 7,617	9,090	$ 7,866
Net income	$ 375	$ 518	$ 1,030	$ 1,241
Common stock
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Beginning of period (in shares)	683,000,000	683,000,000	683,000,000	683,000,000	683,000,000
Beginning of period	$ 683	$ 683	$ 683	$ 683	$ 683
End of period (in shares)	683,000,000	683,000,000	683,000,000	683,000,000	683,000,000
End of period	$ 683	$ 683	$ 683	$ 683	$ 683
Common stock in treasury
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Beginning of period	$ (10,322)	$ (8,485)	$ (9,989)	$ (7,981)	$ (7,981)
Treasury stock, shares (in shares)	175,000,000	150,000,000	175,000,000	150,000,000	170,000,000	173,000,000	148,000,000	142,000,000
Purchases of treasury stock (in shares)	4,000,000	4,000,000	14,000,000	15,000,000
Purchases of treasury stock	$ (346)	$ (247)	$ (1,089)	$ (1,028)
Stock issued under employee benefit plans and other (in shares)	(2,000,000)	(2,000,000)	(9,000,000)	(7,000,000)
Stock issued under employee benefit plans and other	$ 86	$ 93	$ 496	$ 370
End of period	(10,582)	(8,639)	(10,582)	(8,639)	$ (9,989)
Additional contributed capital
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Beginning of period	5,906	5,916	5,898	5,940	5,940
Purchases of treasury stock	0		46
Stock issued under employee benefit plans and other	20	15	(18)	(9)
End of period	5,926	5,931	5,926	5,931	5,898
Retained earnings
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Beginning of period	15,598	14,484	15,075	14,014	14,014
Adoption of new accounting standards			161	(20)
Stock issued under employee benefit plans and other	(1)	(14)	(84)	(59)
Dividends declared on common stock	(117)	(102)	(327)	(290)
End of period	15,849	14,886	15,849	14,886	15,075
Net income	369	518	1,024	1,241
Accumulated other comprehensive income (loss)
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Beginning of period	(4,086)	(3,756)	(3,823)	(3,539)	(3,539)
Adoption of new accounting standards			(161)	(3)
Other comprehensive income (loss)	(202)	2	(304)	(212)
End of period	(4,288)	(3,754)	(4,288)	(3,754)	(3,823)
Total Baxter stockholders' equity
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Beginning of period	7,779	8,842	7,844	9,117	9,117
Adoption of new accounting standards				(23)
Other comprehensive income (loss)	(202)	2	(304)	(212)
Purchases of treasury stock	(346)	(247)	(1,043)	(1,028)
Stock issued under employee benefit plans and other	105	94	394	302
Dividends declared on common stock	(117)	(102)	(327)	(290)
End of period	7,588	9,107	7,588	9,107	7,844
Net income	369	518	1,024	1,241
Noncontrolling interests
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Beginning of period	24	(12)	22	(8)	(8)
Change in noncontrolling interests	(1)	(5)	1	(9)
End of period	29	(17)	29	(17)	22
Net income	$ 6		6
As previously reported
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Beginning of period		8,869	7,816	9,116	9,116
Adoption of new accounting standards				(19)
Net income		544		1,276
Other comprehensive income (loss)		(40)		(235)
Purchases of treasury stock		(247)		(1,028)
Stock issued under employee benefit plans and other		94		302
Dividends declared on common stock		(102)		(290)
Change in noncontrolling interests		(5)		(9)
End of period		9,113		9,113	$ 7,816
Net income		$ 544		$ 1,276
As previously reported | Common stock
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Beginning of period (in shares)		683,000,000		683,000,000	683,000,000
Beginning of period		$ 683		$ 683	$ 683
End of period (in shares)		683,000,000		683,000,000
End of period		$ 683		$ 683
As previously reported | Common stock in treasury
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Beginning of period		$ (8,485)		$ (7,981)	(7,981)
Treasury stock, shares (in shares)		150,000,000		150,000,000			148,000,000	142,000,000
Purchases of treasury stock (in shares)		4,000,000		15,000,000
Purchases of treasury stock		$ (247)		$ (1,028)
Stock issued under employee benefit plans and other (in shares)		(2,000,000)		(7,000,000)
Stock issued under employee benefit plans and other		$ 93		$ 370
End of period		(8,639)		(8,639)
As previously reported | Additional contributed capital
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Beginning of period		5,916		5,940	5,940
Stock issued under employee benefit plans and other		15		(9)
End of period		5,931		5,931
As previously reported | Retained earnings
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Beginning of period		14,966		14,483	14,483
Adoption of new accounting standards				(16)
Stock issued under employee benefit plans and other		(14)		(59)
Dividends declared on common stock		(102)		(290)
End of period		15,394		15,394
Net income		544		1,276
As previously reported | Accumulated other comprehensive income (loss)
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Beginning of period		(4,199)		(4,001)	(4,001)
Adoption of new accounting standards				(3)
Other comprehensive income (loss)		(40)		(235)
End of period		(4,239)		(4,239)
As previously reported | Total Baxter stockholders' equity
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Beginning of period		8,881		9,124	9,124
Adoption of new accounting standards				(19)
Other comprehensive income (loss)		(40)		(235)
Purchases of treasury stock		(247)		(1,028)
Stock issued under employee benefit plans and other		94		302
Dividends declared on common stock		(102)		(290)
End of period		9,130		9,130
Net income		544		1,276
As previously reported | Noncontrolling interests
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Beginning of period		(12)		(8)	(8)
Change in noncontrolling interests		(5)		(9)
End of period		(17)		(17)
Restatement impacts
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Beginning of period		(39)	$ 50	(7)	(7)
Adoption of new accounting standards				(4)
Net income		(26)		(35)
Other comprehensive income (loss)		42		23
End of period		(23)		(23)	$ 50
Net income		$ (26)		$ (35)
Restatement impacts | Common stock
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Beginning of period (in shares)		0		0	0
Beginning of period		$ 0		$ 0	$ 0
End of period (in shares)		0		0
End of period		$ 0		$ 0
Restatement impacts | Common stock in treasury
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Beginning of period		$ 0		$ 0	0
Treasury stock, shares (in shares)		0		0			0	0
End of period		$ 0		$ 0
Restatement impacts | Additional contributed capital
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Beginning of period		0		0	0
End of period		0		0
Restatement impacts | Retained earnings
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Beginning of period		(482)		(469)	(469)
Adoption of new accounting standards				(4)
End of period		(508)		(508)
Net income		(26)		(35)
Restatement impacts | Accumulated other comprehensive income (loss)
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Beginning of period		443		462	462
Other comprehensive income (loss)		42		23
End of period		485		485
Restatement impacts | Total Baxter stockholders' equity
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Beginning of period		(39)		(7)	(7)
Adoption of new accounting standards				(4)
Other comprehensive income (loss)		42		23
End of period		(23)		(23)
Net income		(26)		(35)
Restatement impacts | Noncontrolling interests
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Beginning of period		0		0	$ 0
End of period		$ 0		$ 0