CONSOLIDATED STATEMENT OF EQUITY - USD ($) $ in Millions	Total IBM Stockholders' Equity Cumulative Effect, Period of Adoption, Adjustment	[1]	Total IBM Stockholders' Equity	Common Stock and Additional Paid-in Capital	Retained Earnings Cumulative Effect, Period of Adoption, Adjustment	[1]	Retained Earnings	Treasury Stock	Accumulated Other Comprehensive Income/(Loss)	Non-Controlling Interests	Cumulative Effect, Period of Adoption, Adjustment	[1]	Total
Balance at the Beginning of the Period at Dec. 31, 2019	$ (66)		$ 20,841	$ 55,895	$ (66)		$ 162,954	$ (169,413)	$ (28,597)	$ 144	$ (66)		$ 20,985
Net income plus other comprehensive income/(loss):
Net income			1,175				1,175						1,175
Other comprehensive income/(loss)			(686)						(686)				(686)
Total comprehensive income/(loss)			489										489
Cash dividends paid - common stock			(1,440)				(1,440)						(1,440)
Common stock issued under employee plans			197	197									197
Purchases and sales of treasury stock under employee plans - net			(21)				3	(24)					(21)
Changes in noncontrolling interests										(15)			(15)
Balance at the End of the Period at Mar. 31, 2020			19,999	56,092			162,626	(169,437)	(29,283)	129			20,128
Balance at the Beginning of the Period at Dec. 31, 2020			20,597	56,556			162,717	(169,339)	(29,337)	129			20,727
Net income plus other comprehensive income/(loss):
Net income			955				955						955
Other comprehensive income/(loss)			1,080						1,080				1,080
Total comprehensive income/(loss)			2,036										2,036
Cash dividends paid - common stock			(1,457)				(1,457)						(1,457)
Common stock issued under employee plans			232	232									232
Purchases and sales of treasury stock under employee plans - net			(18)				2	(21)					(18)
Changes in noncontrolling interests										(6)			(6)
Balance at the End of the Period at Mar. 31, 2021			$ 21,389	$ 56,788			$ 162,218	$ (169,360)	$ (28,257)	$ 124			$ 21,513

[1] Reflects the adoption of the FASB guidance on credit losses. Refer to note 2, “Accounting Changes.”