Consolidated Statements of Operations - USD ($) shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Product revenue	$ 2,579	$ 2,737	$ 2,711
Service revenue	3,937	3,806	3,662
Total revenue	6,516	6,543	6,373
Cost of products	(2,026)	(2,102)	(2,072)
Cost of services	(2,626)	(2,659)	(2,832)
Selling, general and administrative expenses	(932)	(926)	(1,042)
Research and development expenses	(256)	(242)	(230)
Restructuring-related charges	0	15	62
Total operating expenses	5,840	5,944	6,238
Income from operations	676	599	135
Interest expense	(163)	(170)	(173)
Other (expense), net	(31)	(50)	(57)
Income (loss) from continuing operations before income taxes	482	379	(95)
Income tax expense	242	92	55
Income (loss) from continuing operations	240	287	(150)
Loss (income) from discontinued operations	(5)	(13)	(24)
Net income (loss)	235	274	(174)
Net income attributable to noncontrolling interests	3	4	4
Net income (loss) attributable to NCR	232	270	(178)
Amounts attributable to NCR common stockholders:
Income (loss) from continuing operations	237	283	(154)
Series A convertible preferred stock dividends	(47)	(49)	(4)
Deemed dividend on modification of Series A convertible preferred stock	(4)	0	0
Deemed dividend on preferred stock redemption	(58)	0	0
Income (loss) from continuing operations attributable to common stockholders	128	234	(158)
Loss (income) from discontinued operations	(5)	(13)	(24)
Net income (loss) attributable to NCR common stockholders	$ 123	$ 221	$ (182)
Income (loss) per share attributable to NCR common stockholders:
Basic (in dollars per share)	$ 1.05	$ 1.86	$ (0.94)
Diluted (in dollars per share)	1.01	1.80	(0.94)
Net income (loss) per common share
Basic (in dollars per share)	1.01	1.76	(1.09)
Total diluted earnings (loss) per share	$ 0.97	$ 1.71	$ (1.09)
Weighted average common shares outstanding
Basic (in shares)	121.9	125.6	167.6
Diluted (continuing operations)	127.0	157.4	167.6
Diluted (net income)	127.0	129.2	167.6