Condensed Consolidated Statements of Changes in Equity (unaudited) - USD ($) $ in Millions	Total	Cumulative Effect, Period of Adoption, Adjustment	Total Baxter stockholders' equity	Total Baxter stockholders' equity Cumulative Effect, Period of Adoption, Adjustment	Common stock	Common stock in treasury	Additional contributed capital	Retained earnings	Retained earnings Cumulative Effect, Period of Adoption, Adjustment	Accumulated other comprehensive income (loss)	Noncontrolling interests
Beginning of period (in shares) at Dec. 31, 2019					683,000,000
Beginning of period at Dec. 31, 2019	$ 7,912	$ (4)	$ 7,882	$ (4)	$ 683	$ (10,764)	$ 5,955	$ 15,718	$ (4)	$ (3,710)	$ 30
Beginning of period, treasury shares (in shares) at Dec. 31, 2019						177,000,000
Gains (losses)
Net income	939		934					934			5
Other comprehensive income (loss)	(129)		(129)							(129)
Stock issued under employee benefit plans and other (in shares)						(4,000,000)
Stock issued under employee benefit plans and other	247		247			$ 193	54
Dividends declared on common stock	(363)		(363)					(363)
End of period (in shares) at Sep. 30, 2020					683,000,000
End of period at Sep. 30, 2020	8,602		8,567		$ 683	$ (10,571)	6,009	16,285		(3,839)	35
End of period, treasury shares (in shares) at Sep. 30, 2020						173,000,000
Beginning of period (in shares) at Jun. 30, 2020					683,000,000
Beginning of period at Jun. 30, 2020	8,160		8,128		$ 683	$ (10,597)	5,975	16,055		(3,988)	32
Beginning of period, treasury shares (in shares) at Jun. 30, 2020						173,000,000
Gains (losses)
Net income	359		356					356			3
Other comprehensive income (loss)	149		149							149
Stock issued under employee benefit plans and other (in shares)						0
Stock issued under employee benefit plans and other	60		60			$ 26	34
Dividends declared on common stock	(126)		(126)					(126)
End of period (in shares) at Sep. 30, 2020					683,000,000
End of period at Sep. 30, 2020	$ 8,602		8,567		$ 683	$ (10,571)	6,009	16,285		(3,839)	35
End of period, treasury shares (in shares) at Sep. 30, 2020						173,000,000
Beginning of period (in shares) at Dec. 31, 2020	683,494,944				683,000,000
Beginning of period at Dec. 31, 2020	$ 8,726		8,689		$ 683	$ (11,051)	6,043	16,328		(3,314)	37
Beginning of period, treasury shares (in shares) at Dec. 31, 2020	178,580,208					179,000,000
Gains (losses)
Net income	$ 1,053		1,046					1,046			7
Other comprehensive income (loss)	$ (168)		(168)							(168)
Purchases of treasury stock (in shares)	7,300,000					7,000,000
Purchases of treasury stock	$ (600)		(600)			$ (600)	0
Stock issued under employee benefit plans and other (in shares)						(3,000,000)
Stock issued under employee benefit plans and other	210		210			$ 122	88	0
Dividends declared on common stock	(407)		(407)					(407)
Change in noncontrolling interests	$ 1										1
End of period (in shares) at Sep. 30, 2021	683,494,944				683,000,000
End of period at Sep. 30, 2021	$ 8,815		8,770		$ 683	$ (11,529)	6,131	16,967		(3,482)	45
End of period, treasury shares (in shares) at Sep. 30, 2021	182,847,640					183,000,000
Beginning of period (in shares) at Jun. 30, 2021					683,000,000
Beginning of period at Jun. 30, 2021	$ 8,535		8,494		$ 683	$ (11,561)	6,090	16,658		(3,376)	41
Beginning of period, treasury shares (in shares) at Jun. 30, 2021						184,000,000
Gains (losses)
Net income	452		450					450			2
Other comprehensive income (loss)	(106)		(106)							(106)
Stock issued under employee benefit plans and other (in shares)						(1,000,000)
Stock issued under employee benefit plans and other	73		73			$ 32	41
Dividends declared on common stock	(141)		(141)					(141)
Change in noncontrolling interests	$ 2										2
End of period (in shares) at Sep. 30, 2021	683,494,944				683,000,000
End of period at Sep. 30, 2021	$ 8,815		$ 8,770		$ 683	$ (11,529)	$ 6,131	$ 16,967		$ (3,482)	$ 45
End of period, treasury shares (in shares) at Sep. 30, 2021	182,847,640					183,000,000