Condensed Consolidating Supplemental Guarantor Information - Statement of Operations and Comprehensive Income (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Total revenue	$ 1,550	$ 1,663	$ 4,604	$ 4,734
Selling, general and administrative expenses	226	220	732	678
Research and development expenses	59	53	190	178
Asset impairment charges	0	0	183	0
Total operating expenses	1,425	1,464	4,476	4,245
Income from operations	125	199	128	489
Interest expense	(43)	(42)	(125)	(122)
Other (expense), net	(10)	(7)	(24)	(16)
Income (loss) from continuing operations before income taxes	72	150	(21)	351
Income tax expense (benefit)	(15)	31	(20)	78
Income (loss) from continuing operations before earnings in subsidiaries	87	119	(1)	273
Equity in earnings of consolidated subsidiaries	0	0	0	0
Income (loss) from continuing operations	87	119	(1)	273
Income from discontinued operations, net of tax	(1)	0	(38)	5
Net income (loss)	86	119	(39)	278
Net income attributable to noncontrolling interests	2	1	2	1
Net (loss) income attributable to NCR	84	118	(41)	277
Total comprehensive income (loss)	69	119	(85)	293
Less comprehensive income (loss) attributable to noncontrolling interests	3	(1)	0	(1)
Comprehensive income (loss) attributable to NCR	66	120	(85)	294
Eliminations
Total revenue	(55)	(51)	(156)	(215)
Selling, general and administrative expenses	0	0	0	0
Research and development expenses	0	0	0	0
Asset impairment charges	0		0
Total operating expenses	(55)	(51)	(156)	(215)
Income from operations	0	0	0	0
Interest expense	3	2	6	4
Other (expense), net	(3)	(2)	(6)	(4)
Income (loss) from continuing operations before income taxes	0	0	0	0
Income tax expense (benefit)	0	0	0	0
Income (loss) from continuing operations before earnings in subsidiaries	0	0	0	0
Equity in earnings of consolidated subsidiaries	(64)	(160)	(338)	(383)
Income (loss) from continuing operations	(64)	(160)	(338)	(383)
Income from discontinued operations, net of tax	0	0	0	0
Net income (loss)	(64)	(160)	(338)	(383)
Net income attributable to noncontrolling interests	0	0	0	0
Net (loss) income attributable to NCR	(64)	(160)	(338)	(383)
Total comprehensive income (loss)	(42)	(177)	(250)	(435)
Less comprehensive income (loss) attributable to noncontrolling interests	0	0	0	0
Comprehensive income (loss) attributable to NCR	(42)	(177)	(250)	(435)
Parent Issuer
Total revenue	775	856	2,346	2,470
Selling, general and administrative expenses	132	110	426	373
Research and development expenses	40	43	115	115
Asset impairment charges	1		166
Total operating expenses	755	757	2,450	2,229
Income from operations	20	99	(104)	241
Interest expense	(42)	(41)	(121)	(118)
Other (expense), net	0	(13)	(15)	(41)
Income (loss) from continuing operations before income taxes	(22)	45	(240)	82
Income tax expense (benefit)	(80)	14	(56)	23
Income (loss) from continuing operations before earnings in subsidiaries	58	31	(184)	59
Equity in earnings of consolidated subsidiaries	26	87	179	213
Income (loss) from continuing operations	84	118	(5)	272
Income from discontinued operations, net of tax	0	0	(36)	5
Net income (loss)	84	118	(41)	277
Net income attributable to noncontrolling interests	0	0	0	0
Net (loss) income attributable to NCR	84	118	(41)	277
Total comprehensive income (loss)	66	120	(85)	294
Less comprehensive income (loss) attributable to noncontrolling interests	0	0	0	0
Comprehensive income (loss) attributable to NCR	66	120	(85)	294
Guarantor Subsidiary
Total revenue	16	19	61	86
Selling, general and administrative expenses	1	1	2	3
Research and development expenses	0	0	0	0
Asset impairment charges	0		0
Total operating expenses	9	10	27	39
Income from operations	7	9	34	47
Interest expense	0	0	0	0
Other (expense), net	2	1	4	0
Income (loss) from continuing operations before income taxes	9	10	38	47
Income tax expense (benefit)	2	1	6	19
Income (loss) from continuing operations before earnings in subsidiaries	7	9	32	28
Equity in earnings of consolidated subsidiaries	38	73	159	170
Income (loss) from continuing operations	45	82	191	198
Income from discontinued operations, net of tax	0	0	0	0
Net income (loss)	45	82	191	198
Net income attributable to noncontrolling interests	0	0	0	0
Net (loss) income attributable to NCR	45	82	191	198
Total comprehensive income (loss)	40	95	148	235
Less comprehensive income (loss) attributable to noncontrolling interests	0	0	0	0
Comprehensive income (loss) attributable to NCR	40	95	148	235
Non-Guarantor Subsidiaries
Total revenue	814	839	2,353	2,393
Selling, general and administrative expenses	93	109	304	302
Research and development expenses	19	10	75	63
Asset impairment charges	(1)		17
Total operating expenses	716	748	2,155	2,192
Income from operations	98	91	198	201
Interest expense	(4)	(3)	(10)	(8)
Other (expense), net	(9)	7	(7)	29
Income (loss) from continuing operations before income taxes	85	95	181	222
Income tax expense (benefit)	63	16	30	36
Income (loss) from continuing operations before earnings in subsidiaries	22	79	151	186
Equity in earnings of consolidated subsidiaries	0	0	0	0
Income (loss) from continuing operations	22	79	151	186
Income from discontinued operations, net of tax	(1)	0	(2)	0
Net income (loss)	21	79	149	186
Net income attributable to noncontrolling interests	2	1	2	1
Net (loss) income attributable to NCR	19	78	147	185
Total comprehensive income (loss)	5	81	102	199
Less comprehensive income (loss) attributable to noncontrolling interests	3	(1)	0	(1)
Comprehensive income (loss) attributable to NCR	2	82	102	200
Product
Total revenue	534	657	1,585	1,829
Cost of products	473	528	1,344	1,430
Product | Eliminations
Total revenue	(55)	(51)	(156)	(215)
Cost of products	(55)	(51)	(156)	(215)
Product | Parent Issuer
Total revenue	234	338	769	948
Cost of products	225	264	690	728
Product | Guarantor Subsidiary
Total revenue	7	13	36	66
Cost of products	4	8	15	30
Product | Non-Guarantor Subsidiaries
Total revenue	348	357	936	1,030
Cost of products	299	307	795	887
Service
Total revenue	1,016	1,006	3,019	2,905
Cost of products	667	663	2,027	1,959
Service | Eliminations
Total revenue	0	0	0	0
Cost of products	0	0	0	0
Service | Parent Issuer
Total revenue	541	518	1,577	1,522
Cost of products	357	340	1,053	1,013
Service | Guarantor Subsidiary
Total revenue	9	6	25	20
Cost of products	4	1	10	6
Service | Non-Guarantor Subsidiaries
Total revenue	466	482	1,417	1,363
Cost of products	$ 306	$ 322	$ 964	$ 940