Condensed Consolidating Supplemental Guarantor Information Statement of Operations and Comprehensive Income (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	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	$ 1,782	$ 1,663	$ 1,593	$ 1,478	$ 1,802	$ 1,677	$ 1,620	$ 1,444	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
Restructuring-related charges										15	62
Total operating expenses									5,840	5,944	6,238
Income (loss) from operations	181	200	178	117	146	189	163	101	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 (benefit)									242	92	55
Income (loss) from continuing operations before earning in subsidiaries									240	287	(150)
Equity in earnings of consolidated subsidiaries									0	0	0
Income from continuing operations									240	287	(150)
Loss (income) from discontinued operations									(5)	(13)	(24)
Net income (loss)									235	274	(174)
Net income									3	4	4
Net (loss) income attributable to NCR	$ (56)	$ 106	$ 90	$ (17)	$ 45	$ 92	$ 63	$ 21	232	270	(178)
Total comprehensive income (loss)									239	214	(191)
Less comprehensive income (loss) attributable to noncontrolling interests									1	(1)	1
Comprehensive (loss) income attributable to NCR common stockholders									238	215	(192)
Parent Company [Member]
Product revenue									1,329	1,293	1,189
Service revenue									2,051	1,962	1,868
Total revenue									3,380	3,255	3,057
Cost of products									1,044	1,028	904
Cost of services									1,378	1,369	1,289
Selling, general and administrative expenses									502	534	567
Research and development expenses									192	164	133
Restructuring-related charges									0
Restructuring-related charges										3	36
Total operating expenses									3,116	3,098	2,929
Income (loss) from operations									264	157	128
Interest expense									(204)	(165)	(168)
Other (expense), net									11	(20)	(47)
Income (loss) from continuing operations before income taxes									71	(28)	(87)
Income tax expense (benefit)									113	(20)	(38)
Income (loss) from continuing operations before earning in subsidiaries									(42)	(8)	(49)
Equity in earnings of consolidated subsidiaries									279	291	(104)
Income from continuing operations									237	283	(153)
Loss (income) from discontinued operations									(5)	(13)	(25)
Net income (loss)									232	270	(178)
Net income									0	0	0
Net (loss) income attributable to NCR									232	270	(178)
Total comprehensive income (loss)									238	215	(192)
Less comprehensive income (loss) attributable to noncontrolling interests									0	0	0
Comprehensive (loss) income attributable to NCR common stockholders									238	215	(192)
Guarantor Subsidiary [Member]
Product revenue									91	111	105
Service revenue									29	36	33
Total revenue									120	147	138
Cost of products									37	50	43
Cost of services									10	12	13
Selling, general and administrative expenses									3	4	4
Research and development expenses									0	0	0
Restructuring-related charges									0
Restructuring-related charges										0	0
Total operating expenses									50	66	60
Income (loss) from operations									70	81	78
Interest expense									0	0	0
Other (expense), net									1	(23)	4
Income (loss) from continuing operations before income taxes									71	58	82
Income tax expense (benefit)									107	21	52
Income (loss) from continuing operations before earning in subsidiaries									(36)	37	30
Equity in earnings of consolidated subsidiaries									291	304	(161)
Income from continuing operations									255	341	(131)
Loss (income) from discontinued operations									0	0	0
Net income (loss)									255	341	(131)
Net income									0	0	0
Net (loss) income attributable to NCR									255	341	(131)
Total comprehensive income (loss)									269	277	(154)
Less comprehensive income (loss) attributable to noncontrolling interests									0	0	0
Comprehensive (loss) income attributable to NCR common stockholders									269	277	(154)
Non-Guarantor Subsidiaries [Member]
Product revenue									1,454	1,768	2,339
Service revenue									1,857	1,808	1,761
Total revenue									3,311	3,576	4,100
Cost of products									1,240	1,459	2,047
Cost of services									1,238	1,278	1,530
Selling, general and administrative expenses									427	388	471
Research and development expenses									64	78	97
Restructuring-related charges									0
Restructuring-related charges										12	26
Total operating expenses									2,969	3,215	4,171
Income (loss) from operations									342	361	(71)
Interest expense									(10)	(10)	(10)
Other (expense), net									8	(2)	(9)
Income (loss) from continuing operations before income taxes									340	349	(90)
Income tax expense (benefit)									22	91	41
Income (loss) from continuing operations before earning in subsidiaries									318	258	(131)
Equity in earnings of consolidated subsidiaries									0	0	0
Income from continuing operations									318	258	(131)
Loss (income) from discontinued operations									0	0	1
Net income (loss)									318	258	(130)
Net income									3	4	4
Net (loss) income attributable to NCR									315	254	(134)
Total comprehensive income (loss)									317	195	(145)
Less comprehensive income (loss) attributable to noncontrolling interests									1	(1)	1
Comprehensive (loss) income attributable to NCR common stockholders									316	196	(146)
Consolidation, Eliminations [Member]
Product revenue									(295)	(435)	(922)
Service revenue									0	0	0
Total revenue									(295)	(435)	(922)
Cost of products									(295)	(435)	(922)
Cost of services									0	0	0
Selling, general and administrative expenses									0	0	0
Research and development expenses									0	0	0
Restructuring-related charges									0
Restructuring-related charges										0	0
Total operating expenses									(295)	(435)	(922)
Income (loss) from operations									0	0	0
Interest expense									51	5	5
Other (expense), net									(51)	(5)	(5)
Income (loss) from continuing operations before income taxes									0	0	0
Income tax expense (benefit)									0	0	0
Income (loss) from continuing operations before earning in subsidiaries									0	0	0
Equity in earnings of consolidated subsidiaries									(570)	(595)	265
Income from continuing operations									(570)	(595)	265
Loss (income) from discontinued operations									0	0	0
Net income (loss)									(570)	(595)	265
Net income									0	0	0
Net (loss) income attributable to NCR									(570)	(595)	265
Total comprehensive income (loss)									(585)	(473)	300
Less comprehensive income (loss) attributable to noncontrolling interests									0	0	0
Comprehensive (loss) income attributable to NCR common stockholders									$ (585)	$ (473)	$ 300