QUARTERLY FINANCIAL DATA (UNAUDITED) - Changes in Equity (Details) - USD ($) $ 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	Dec. 31, 2016
Error Corrections and Prior Period Adjustments Restatement
Beginning of year		$ 7,803	$ 7,593	$ 7,866	$ 9,090	$ 8,830	$ 9,062	$ 9,109	$ 7,866	$ 9,109	$ 7,866	$ 9,109	$ 8,221
Common stock, issued (in shares)	683,494,944		683,494,944	683,494,944	683,494,944	683,494,944	683,494,944	683,494,944	683,494,944	683,494,944	683,494,944	683,494,944
Treasury stock, shares (in shares)	177,340,358		173,275,586	173,447,198	170,495,859	150,213,621	148,485,202	146,993,164	173,275,586	148,485,202	177,340,358	170,495,859
Adoption of new accounting standards				$ 0				$ (23)	$ 0	$ (23)	$ 0	$ (25)
Net income attributable to Baxter stockholders	$ (23)	369	$ 313	342	$ 305	$ 518	$ 341	382	655	723	1,001	1,546	602
Other comprehensive income (loss)			(4)	(98)			(329)	115	(102)	(214)	274	(281)	722
Purchases of common stock			(111)	(586)			(259)	(522)	(697)	(781)	$ (1,247)	$ (2,475)	$ (564)
Purchases of common stock (in shares)											16,500,000	35,800,000	9,200,000
Stock issued under employee benefit plans and other			123	166			123	85	289	208	$ 445	$ 354	$ 426
Dividends declared on common stock			(112)	(98)			(102)	(86)	(210)	(188)	(435)	(392)	(334)
Changes in noncontrolling interests			1	1			(6)	2	2	(4)	(2)	30	2
End of year	$ 7,912		7,803	7,593	7,866	9,090	8,830	9,062	7,803	8,830	7,912	7,866	9,109
As previously reported
Error Corrections and Prior Period Adjustments Restatement
Beginning of year		7,836	7,669	7,816	9,113	8,869	9,093	9,116	7,816	9,116	7,816	9,116	8,280
Adoption of new accounting standards				0				(19)	0	(19)		(21)
Net income attributable to Baxter stockholders			343	347			343	389	690	732		1,624	717
Other comprehensive income (loss)			(77)	23			(323)	128	(54)	(195)		(420)	555
Purchases of common stock			(111)	(586)			(259)	(522)	(697)	(781)		(2,475)	(564)
Stock issued under employee benefit plans and other			123	166			123	85	289	208		354	426
Dividends declared on common stock			(112)	(98)			(102)	(86)	(210)	(188)		(392)	(334)
Changes in noncontrolling interests			1	1			(6)	2	2	(4)		30	2
End of year			7,836	7,669	7,816	9,113	8,869	9,093	7,836	8,869		7,816	9,116
Restatement impacts
Error Corrections and Prior Period Adjustments Restatement
Beginning of year		(33)	(76)	50	(23)	(39)	(31)	(7)	50	(7)	50	(7)	(59)
Adoption of new accounting standards								(4)		(4)		(4)
Net income attributable to Baxter stockholders			(30)	(5)			(2)	(7)	(35)	(9)		(78)	(115)
Other comprehensive income (loss)			73	(121)			(6)	(13)	(48)	(19)		139	167
End of year			(33)	(76)	$ 50	(23)	(39)	(31)	(33)	(39)		50	(7)
Common stock
Error Corrections and Prior Period Adjustments Restatement
Beginning of year		683	$ 683	$ 683		683	$ 683	$ 683	$ 683	$ 683	$ 683	$ 683	$ 683
Common stock, issued (in shares)	683,000,000		683,000,000	683,000,000	683,000,000		683,000,000	683,000,000	683,000,000	683,000,000	683,000,000	683,000,000	683,000,000	683,000,000
End of year	$ 683		$ 683	$ 683	$ 683		$ 683	$ 683	$ 683	$ 683	$ 683	$ 683	$ 683
Common stock | As previously reported
Error Corrections and Prior Period Adjustments Restatement
Beginning of year		683	$ 683	$ 683		683	$ 683	$ 683	$ 683	$ 683	683	$ 683	$ 683
Common stock, issued (in shares)			683,000,000	683,000,000	683,000,000		683,000,000	683,000,000	683,000,000	683,000,000		683,000,000	683,000,000	683,000,000
End of year			$ 683	$ 683	$ 683		$ 683	$ 683	$ 683	$ 683		$ 683	$ 683
Common stock | Restatement impacts
Error Corrections and Prior Period Adjustments Restatement
Beginning of year		0	$ 0	$ 0		0	$ 0	$ 0	$ 0	$ 0	0	$ 0	$ 0
Common stock, issued (in shares)			0	0	0		0	0	0	0		0	0	0
End of year			$ 0	$ 0	$ 0		$ 0	$ 0	$ 0	$ 0		$ 0	$ 0
Common stock in treasury
Error Corrections and Prior Period Adjustments Restatement
Beginning of year		(10,322)	$ (10,284)	$ (9,989)		(8,485)	$ (8,354)	$ (7,981)	$ (9,989)	$ (7,981)	$ (9,989)	$ (7,981)	$ (7,995)
Treasury stock, shares (in shares)	177,000,000		173,000,000	173,000,000	170,000,000		148,000,000	147,000,000	173,000,000	148,000,000	177,000,000	170,000,000	142,000,000	144,000,000
Purchases of common stock			$ (157)	$ (586)			$ (259)	$ (522)	$ (743)	$ (781)	$ (1,293)	$ (2,415)	$ (564)
Purchases of common stock (in shares)			2,000,000	8,000,000			3,000,000	8,000,000	10,000,000	11,000,000	16,000,000	36,000,000	9,000,000
Stock issued under employee benefit plans and other			$ 119	$ 291			$ 128	$ 149	$ 410	$ 277	$ 518	$ 407	$ 578
Stock issued under employee benefit plans and other (in shares)			(2,000,000)	(5,000,000)			(2,000,000)	(3,000,000)	(7,000,000)	(5,000,000)	9,000,000	8,000,000	11,000,000
End of year	$ (10,764)		$ (10,322)	$ (10,284)	$ (9,989)		$ (8,485)	$ (8,354)	$ (10,322)	$ (8,485)	$ (10,764)	$ (9,989)	$ (7,981)
Common stock in treasury | As previously reported
Error Corrections and Prior Period Adjustments Restatement
Beginning of year		(10,322)	$ (10,284)	$ (9,989)		(8,485)	$ (8,354)	$ (7,981)	$ (9,989)	$ (7,981)	(9,989)	$ (7,981)	$ (7,995)
Treasury stock, shares (in shares)			173,000,000	173,000,000	170,000,000		148,000,000	147,000,000	173,000,000	148,000,000		170,000,000	142,000,000	144,000,000
Purchases of common stock			$ (157)	$ (586)			$ (259)	$ (522)	$ (743)	$ (781)		$ (2,415)	$ (564)
Purchases of common stock (in shares)			2,000,000	8,000,000			3,000,000	8,000,000	10,000,000	11,000,000		36,000,000	9,000,000
Stock issued under employee benefit plans and other			$ 119	$ 291			$ 128	$ 149	$ 410	$ 277		$ 407	$ 578
Stock issued under employee benefit plans and other (in shares)			(2,000,000)	(5,000,000)			(2,000,000)	(3,000,000)	(7,000,000)	(5,000,000)		(8,000,000)	(11,000,000)
End of year			$ (10,322)	$ (10,284)	$ (9,989)		$ (8,485)	$ (8,354)	$ (10,322)	$ (8,485)		$ (9,989)	$ (7,981)
Common stock in treasury | Restatement impacts
Error Corrections and Prior Period Adjustments Restatement
Beginning of year		0	$ 0	$ 0		0	$ 0	$ 0	$ 0	$ 0	0	$ 0	$ 0
Treasury stock, shares (in shares)			0	0	0		0	0	0	0		0	0	0
End of year			$ 0	$ 0	$ 0		$ 0	$ 0	$ 0	$ 0		$ 0	$ 0
Additional contributed capital
Error Corrections and Prior Period Adjustments Restatement
Beginning of year		5,906	5,839	5,898		5,916	5,912	5,940	5,898	5,940	5,898	5,940	5,958
Purchases of common stock			46						46		46	(60)
Stock issued under employee benefit plans and other			21	(59)			4	(28)	(38)	(24)	11	18	(18)
End of year	5,955		5,906	5,839	5,898		5,916	5,912	5,906	5,916	5,955	5,898	5,940
Additional contributed capital | As previously reported
Error Corrections and Prior Period Adjustments Restatement
Beginning of year		5,906	5,839	5,898		5,916	5,912	5,940	5,898	5,940	5,898	5,940	5,958
Purchases of common stock			46						46			(60)	0
Stock issued under employee benefit plans and other			21	(59)			4	(28)	(38)	(24)		18	(18)
End of year			5,906	5,839	5,898		5,916	5,912	5,906	5,916		5,898	5,940
Additional contributed capital | Restatement impacts
Error Corrections and Prior Period Adjustments Restatement
Beginning of year		0	0	0		0	0	0	0	0	0	0	0
End of year			0	0	0		0	0	0	0		0	0
Retained earnings
Error Corrections and Prior Period Adjustments Restatement
Beginning of year		15,598	15,414	15,075		14,484	14,254	14,014	15,075	14,014	15,075	14,014	13,846
Adoption of new accounting standards				161				(20)	161	(20)	161	(22)
Net income attributable to Baxter stockholders			313	342			341	382	655	723	1,001	1,546	602
Stock issued under employee benefit plans and other			(17)	(66)			(9)	(36)	(83)	(45)	(84)	(71)	(134)
Dividends declared on common stock			(112)	(98)			(102)	(86)	(210)	(188)	(435)	(392)	(334)
End of year	15,718		15,598	15,414	15,075		14,484	14,254	15,598	14,484	15,718	15,075	14,014
Retained earnings | As previously reported
Error Corrections and Prior Period Adjustments Restatement
Beginning of year		16,184	15,970	15,626		14,966	14,734	14,483	15,626	14,483	15,626	14,483	14,200
Adoption of new accounting standards				161				(16)	161	(16)		(18)
Net income attributable to Baxter stockholders			343	347			343	389	690	732		1,624	717
Stock issued under employee benefit plans and other			(17)	(66)			(9)	(36)	(83)	(45)		(71)	(134)
Dividends declared on common stock			(112)	(98)			(102)	(86)	(210)	(188)		(392)	(334)
End of year			16,184	15,970	15,626		14,966	14,734	16,184	14,966		15,626	14,483
Retained earnings | Restatement impacts
Error Corrections and Prior Period Adjustments Restatement
Beginning of year		(586)	(556)	(551)		(482)	(480)	(469)	(551)	(469)	(551)	(469)	(354)
Adoption of new accounting standards								(4)		(4)		(4)
Net income attributable to Baxter stockholders			(30)	(5)			(2)	(7)	(35)	(9)		(78)	(115)
End of year			(586)	(556)	(551)		(482)	(480)	(586)	(482)		(551)	(469)
Accumulated other comprehensive income (loss)
Error Corrections and Prior Period Adjustments Restatement
Beginning of year		(4,086)	(4,082)	(3,823)		(3,756)	(3,427)	(3,539)	(3,823)	(3,539)	(3,823)	(3,539)	(4,261)
Adoption of new accounting standards				(161)				(3)	(161)	(3)	(161)	(3)
Other comprehensive income (loss)			(4)	(98)			(329)	115	(102)	(214)	274	(281)	722
End of year	(3,710)		(4,086)	(4,082)	(3,823)		(3,756)	(3,427)	(4,086)	(3,756)	(3,710)	(3,823)	(3,539)
Accumulated other comprehensive income (loss) | As previously reported
Error Corrections and Prior Period Adjustments Restatement
Beginning of year		(4,639)	(4,562)	(4,424)		(4,199)	(3,876)	(4,001)	(4,424)	(4,001)	(4,424)	(4,001)	(4,556)
Adoption of new accounting standards				(161)				(3)	(161)	(3)		(3)
Other comprehensive income (loss)			(77)	23			(323)	128	(54)	(195)		(420)	555
End of year			(4,639)	(4,562)	(4,424)		(4,199)	(3,876)	(4,639)	(4,199)		(4,424)	(4,001)
Accumulated other comprehensive income (loss) | Restatement impacts
Error Corrections and Prior Period Adjustments Restatement
Beginning of year		553	480	601		443	449	462	601	462	601	462	295
Other comprehensive income (loss)			73	(121)			(6)	(13)	(48)	(19)		139	167
End of year			553	480	601		443	449	553	443		601	462
Total Baxter stockholders' equity
Error Corrections and Prior Period Adjustments Restatement
Beginning of year		7,779	7,570	7,844		8,842	9,068	9,117	7,844	9,117	7,844	9,117	8,231
Adoption of new accounting standards								(23)		(23)		(25)
Net income attributable to Baxter stockholders			313	342			341	382	655	723	1,001	1,546	602
Other comprehensive income (loss)			(4)	(98)			(329)	115	(102)	(214)	274	(281)	722
Purchases of common stock			(111)	(586)			(259)	(522)	(697)	(781)	(1,247)	(2,475)	(564)
Stock issued under employee benefit plans and other			123	166			123	85	289	208	445	354	426
Dividends declared on common stock			(112)	(98)			(102)	(86)	(210)	(188)	(435)	(392)	(334)
End of year	7,882		7,779	7,570	7,844		8,842	9,068	7,779	8,842	7,882	7,844	9,117
Total Baxter stockholders' equity | As previously reported
Error Corrections and Prior Period Adjustments Restatement
Beginning of year		7,812	7,646	7,794		8,881	9,099	9,124	7,794	9,124	7,794	9,124	8,290
Adoption of new accounting standards								(19)		(19)		(21)
Net income attributable to Baxter stockholders			343	347			343	389	690	732		1,624	717
Other comprehensive income (loss)			(77)	23			(323)	128	(54)	(195)		(420)	555
Purchases of common stock			(111)	(586)			(259)	(522)	(697)	(781)		(2,475)	(564)
Stock issued under employee benefit plans and other			123	166			123	85	289	208		354	426
Dividends declared on common stock			(112)	(98)			(102)	(86)	(210)	(188)		(392)	(334)
End of year			7,812	7,646	7,794		8,881	9,099	7,812	8,881		7,794	9,124
Total Baxter stockholders' equity | Restatement impacts
Error Corrections and Prior Period Adjustments Restatement
Beginning of year		(33)	(76)	50		(39)	(31)	(7)	50	(7)	50	(7)	(59)
Adoption of new accounting standards								(4)		(4)		(4)
Net income attributable to Baxter stockholders			(30)	(5)			(2)	(7)	(35)	(9)		(78)	(115)
Other comprehensive income (loss)			73	(121)			(6)	(13)	(48)	(19)		139	167
End of year			(33)	(76)	50		(39)	(31)	(33)	(39)		50	(7)
Noncontrolling interests
Error Corrections and Prior Period Adjustments Restatement
Beginning of year		24	23	22		(12)	(6)	(8)	22	(8)	22	(8)	(10)
Net income attributable to Baxter stockholders											10
Changes in noncontrolling interests			1	1			(6)	2	2	(4)	(2)	30	2
End of year	$ 30		24	23	22		(12)	(6)	24	(12)	30	22	(8)
Noncontrolling interests | As previously reported
Error Corrections and Prior Period Adjustments Restatement
Beginning of year		24	23	22		(12)	(6)	(8)	22	(8)	22	(8)	(10)
Changes in noncontrolling interests			1	1			(6)	2	2	(4)		30	2
End of year			24	23	22		(12)	(6)	24	(12)		22	(8)
Noncontrolling interests | Restatement impacts
Error Corrections and Prior Period Adjustments Restatement
Beginning of year		$ 0	0	0		$ 0	0	0	0	0	$ 0	0	0
End of year			$ 0	$ 0	$ 0		$ 0	$ 0	$ 0	$ 0		$ 0	$ 0