Condensed Consolidated Statements of Operations (Unaudited) - USD ($) shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Income Statement [Abstract]
Product revenue	$ 657	$ 708	$ 1,829	$ 1,932
Service revenue	1,006	969	2,905	2,809
Total revenue	1,663	1,677	4,734	4,741
Cost of products	528	528	1,430	1,487
Cost of services	662	672	1,955	1,951
Selling, general and administrative expenses	220	225	676	678
Research and development expenses	53	56	178	159
Restructuring-related charges	0	7	0	13
Total operating expenses	1,463	1,488	4,239	4,288
Income from operations	200	189	495	453
Interest expense	(42)	(41)	(122)	(130)
Other (expense), net	(8)	(8)	(22)	(33)
Income from continuing operations before income taxes	150	140	351	290
Income tax expense	31	31	78	75
Income from continuing operations	119	109	273	215
(Loss) income from discontinued operations, net of tax	0	(2)	5	(2)
Net income	119	107	278	213
Net income attributable to noncontrolling interests	1	2	1	0
Net income attributable to NCR	118	105	277	213
Amounts attributable to NCR common stockholders:
Income from continuing operations	118	107	272	215
Series A convertible preferred stock dividends	(12)	(13)	(36)	(37)
Deemed dividend on modification of Series A Convertible Preferred Stock	0	0	(4)	0
Deemed dividend on preferred stock redemption	0	0	(58)	0
Income from continuing operations attributable to NCR common stockholders	106	94	174	178
(Loss) income from discontinued operations, net of tax	0	(2)	5	(2)
Net income attributable to NCR common stockholders	$ 106	$ 92	$ 179	$ 176
Income per common share from continuing operations
Basic earnings from continuing operations (in dollars per share)	$ 0.87	$ 0.76	$ 1.43	$ 1.41
Income (Loss) from Continuing Operations, Per Diluted Share	0.77	0.69	1.37	1.37
Net income per common share
Basic (in dollars per share)	0.87	0.74	1.47	1.40
Diluted (in dollars per share)	$ 0.77	$ 0.68	$ 1.41	$ 1.36
Weighted average common shares outstanding
Weighted average outstanding shares of common stock (in shares)	121.5	123.9	121.9	126.0
Diluted (in shares)	153.1	155.4	126.9	156.8