Condensed Consolidated Statements of Operations (Unaudited) - USD ($) shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Income Statement [Abstract]
Product revenue	$ 525	$ 618	$ 1,051	$ 1,172
Service revenue	1,012	975	2,003	1,899
Total revenue	1,537	1,593	3,054	3,071
Cost of products	451	478	871	902
Cost of services	683	654	1,360	1,296
Selling, general and administrative expenses	261	228	506	458
Research and development expenses	65	58	131	125
Asset Impairment Charges	183	0	183	0
Total operating expenses	1,643	1,418	3,051	2,781
(Loss) income from operations	(106)	175	3	290
Interest expense	(41)	(41)	(82)	(80)
Other (expense), net	(9)	(4)	(14)	(9)
(Loss) income from continuing operations before income taxes	(156)	130	(93)	201
Income tax (benefit) expense	(12)	33	(5)	47
(Loss) income from continuing operations	(144)	97	(88)	154
(Loss) income from discontinued operations, net of tax	(2)	5	(37)	5
Net (loss) income	(146)	102	(125)	159
Net (loss) income attributable to noncontrolling interests	(1)	0	0	0
Net (loss) income attributable to NCR	(145)	102	(125)	159
Amounts attributable to NCR common stockholders:
(Loss) income from continuing operations	(143)	97	(88)	154
Series A convertible preferred stock dividends	(12)	(12)	(24)	(24)
Deemed dividend on modification of Series A Convertible Preferred Stock	0	0	0	(4)
Deemed dividend on preferred stock redemption	0	0	0	(58)
(Loss) income from continuing operations attributable to NCR common stockholders	(155)	85	(112)	68
(Loss) income from discontinued operations, net of tax	(2)	5	(37)	5
Net (loss) income attributable to NCR common stockholders	$ (157)	$ 90	$ (149)	$ 73
(Loss) income per common share from continuing operations
Basic earnings from continuing operations (in dollars per share)	$ (1.31)	$ 0.70	$ (0.94)	$ 0.56
Income (Loss) from Continuing Operations, Per Diluted Share	(1.31)	0.64	(0.94)	0.53
Net (loss) income per common share
Basic (in dollars per share)	(1.33)	0.74	(1.26)	0.60
Diluted (in dollars per share)	$ (1.33)	$ 0.67	$ (1.26)	$ 0.57
Weighted average common shares outstanding
Weighted average outstanding shares of common stock (in shares)	117.9	121.4	118.6	122.1
Diluted (in shares)	117.9	152.7	118.6	127.2