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		4,082		4,082				4,082
Other comprehensive income/(loss)		1,208				1,208		1,208
Total comprehensive income/(loss)		5,290						5,290
Cash dividends paid - common stock		(2,724)		(2,724)				(2,724)
Common stock issued under employee plans (Shares - 2,877,775 and 2,945,036 for 2018 and 2017, respectively)		300	300					300
Purchases (Shares - 946,596 and 920,968) and sales (Shares - 351,491 and 347,939) of treasury stock under employee plans - net, for 2018 and 2017, respectively		(88)		15	(103)			(88)
Other treasury shares purchased, not retired (Shares - 11,693,706 and 16,299,114 for 2018 and 2017, respectively)		(2,708)			(2,708)			(2,708)
Changes in noncontrolling interests							(21)	(21)
Balance at the End of the Period at Jun. 30, 2017		18,419	54,235	154,234	(161,860)	(28,189)	125	18,544
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		4,083		4,083				4,083
Other comprehensive income/(loss)		724				724		724
Total comprehensive income/(loss)		4,807						4,807
Cash dividends paid - common stock		(2,819)		(2,819)				(2,819)
Common stock issued under employee plans (Shares - 2,877,775 and 2,945,036 for 2018 and 2017, respectively)		261	261					261
Purchases (Shares - 946,596 and 920,968) and sales (Shares - 351,491 and 347,939) of treasury stock under employee plans - net, for 2018 and 2017, respectively		(86)		12	(98)			(86)
Other treasury shares purchased, not retired (Shares - 11,693,706 and 16,299,114 for 2018 and 2017, respectively)		(1,761)			(1,761)			(1,761)
Changes in noncontrolling interests							(3)	(3)
Balance at the End of the Period at Jun. 30, 2018		$ 18,520	$ 54,827	$ 157,349	$ (165,366)	$ (28,290)	$ 128	$ 18,648

[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".