CONSOLIDATED STATEMENT OF CHANGES IN EQUITY - USD ($) $ in Millions		Total IBM Stockholders' Equity	Common Stock and Additional Paid-in Capital	Retained Earnings	Treasury Stock	Accumulated Other Comprehensive Income/(Loss)	Non-Controlling Interests	Total
Balance at the Beginning of the Period at Dec. 31, 2016		$ 18,246	$ 53,935	$ 152,759	$ (159,050)	$ (29,398)	$ 146	$ 18,392
Equity
Cumulative effect of change in accounting principle | Accounting Standards Update 2016-16, Intra-Entity Transfers of Assets Other Than Inventory	[1]	102		102				102
Net income plus other comprehensive income/(loss)
Net income		6,807		6,807				6,807
Other comprehensive income/(loss)		1,877				1,877		1,877
Total comprehensive income/(loss)		8,684						8,684
Cash dividends paid - common stock		(4,119)		(4,119)				(4,119)
Common stock issued under employee plans (Shares - 3,208,989 and 3,372,586 for 2018 and 2017, respectively)		460	460					460
Purchases (Shares - 978,004 and 960,186) and sales (Shares - 365,600 and 363,335) of treasury stock under employee plans - net, for 2018 and 2017, respectively		(91)		15	(106)			(91)
Other treasury shares purchased, not retired (Shares - 15,982,033 and 22,851,760 for 2018 and 2017, respectively)		(3,655)			(3,655)			(3,655)
Changes in noncontrolling interests							(16)	(16)
Balance at the End of the Period at Sep. 30, 2017		19,627	54,395	155,565	(162,812)	(27,521)	130	19,757
Balance at the Beginning of the Period at Dec. 31, 2017		17,594	54,566	153,126	(163,507)	(26,592)	131	17,725
Equity
Cumulative effect of change in accounting principle | Accounting Standards Update 2014-09, Revenue from Contracts with Customers		524		524				524
Cumulative effect of change in accounting principle | Accounting Standards Updates 2016-01 (Financial Instruments), 2017-12 (Hedging) and 2018-02 (Stranded Tax Effects)	[2]			2,422		(2,422)
Net income plus other comprehensive income/(loss)
Net income		6,777		6,777				6,777
Other comprehensive income/(loss)		1,194				1,194		1,194
Total comprehensive income/(loss)		7,970						7,970
Cash dividends paid - common stock		(4,250)		(4,250)				(4,250)
Common stock issued under employee plans (Shares - 3,208,989 and 3,372,586 for 2018 and 2017, respectively)		421	421					421
Purchases (Shares - 978,004 and 960,186) and sales (Shares - 365,600 and 363,335) of treasury stock under employee plans - net, for 2018 and 2017, respectively		(89)		13	(101)			(89)
Other treasury shares purchased, not retired (Shares - 15,982,033 and 22,851,760 for 2018 and 2017, respectively)		(2,388)			(2,388)			(2,388)
Changes in noncontrolling interests							3	3
Balance at the End of the Period at Sep. 30, 2018		$ 19,784	$ 54,987	$ 158,612	$ (165,995)	$ (27,820)	$ 134	$ 19,918

[1] Reflects the adoption of the FASB guidance on intra-entity transfers of assets.

[2] Reflects the adoption of the FASB guidance on stranded tax effects, hedging and financial instruments. Refer to note 2, "Accounting Changes".