Condensed Consolidating Supplemental Guarantor Information - Statement of Operations and Comprehensive Income (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
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 expense (benefit)	(12)	33	(5)	47
Income (loss) from continuing operations before earnings in subsidiaries	(144)	97	(88)	154
Equity in earnings of consolidated subsidiaries	0	0	0	0
(Loss) income from continuing operations	(144)	97	(88)	154
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
Total comprehensive income (loss)	(189)	99	(154)	174
Less comprehensive income (loss) attributable to noncontrolling interests	(4)	0	(3)	0
Comprehensive (loss) income attributable to NCR	(185)	99	(151)	174
Eliminations
Product revenue	(63)	(60)	(101)	(164)
Service revenue	0	0	0	0
Total revenue	(63)	(60)	(101)	(164)
Cost of products	(63)	(60)	(101)	(164)
Cost of services	0	0	0	0
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	(63)	(60)	(101)	(164)
(Loss) income from operations	0	0	0	0
Interest expense	2	1	3	2
Other (expense), net	(2)	(1)	(3)	(2)
(Loss) income 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	(139)	(169)	(274)	(223)
(Loss) income from continuing operations	(139)	(169)	(274)	(223)
Income from discontinued operations, net of tax	0	0	0	0
Net (loss) income	(139)	(169)	(274)	(223)
Net (loss) income attributable to noncontrolling interests	0	0	0	0
Net (loss) income attributable to NCR	(139)	(169)	(274)	(223)
Total comprehensive income (loss)	(60)	(181)	(208)	(258)
Less comprehensive income (loss) attributable to noncontrolling interests	0	0	0	0
Comprehensive (loss) income attributable to NCR	(60)	(181)	(208)	(258)
Parent Issuer
Product revenue	258	329	535	610
Service revenue	519	511	1,036	1,004
Total revenue	777	840	1,571	1,614
Cost of products	236	257	465	464
Cost of services	354	335	696	673
Selling, general and administrative expenses	130	129	294	263
Research and development expenses	29	42	75	72
Asset Impairment Charges	165		165
Total operating expenses	914	763	1,695	1,472
(Loss) income from operations	(137)	77	(124)	142
Interest expense	(40)	(38)	(79)	(77)
Other (expense), net	(12)	(11)	(15)	(28)
(Loss) income from continuing operations before income taxes	(189)	28	(218)	37
Income tax expense (benefit)	32	11	24	9
Income (loss) from continuing operations before earnings in subsidiaries	(221)	17	(242)	28
Equity in earnings of consolidated subsidiaries	77	80	153	126
(Loss) income from continuing operations	(144)	97	(89)	154
Income from discontinued operations, net of tax	(1)	5	(36)	5
Net (loss) income	(145)	102	(125)	159
Net (loss) income attributable to noncontrolling interests	0	0	0	0
Net (loss) income attributable to NCR	(145)	102	(125)	159
Total comprehensive income (loss)	(185)	99	(151)	174
Less comprehensive income (loss) attributable to noncontrolling interests	0	0	0	0
Comprehensive (loss) income attributable to NCR	(185)	99	(151)	174
Guarantor Subsidiary
Product revenue	24	13	29	53
Service revenue	8	7	16	14
Total revenue	32	20	45	67
Cost of products	7	9	11	22
Cost of services	3	3	6	5
Selling, general and administrative expenses	0	1	1	2
Research and development expenses	0	0	0	0
Asset Impairment Charges	0		0
Total operating expenses	10	13	18	29
(Loss) income from operations	22	7	27	38
Interest expense	0	0	0	0
Other (expense), net	1	(1)	2	(1)
(Loss) income from continuing operations before income taxes	23	6	29	37
Income tax expense (benefit)	2	2	4	18
Income (loss) from continuing operations before earnings in subsidiaries	21	4	25	19
Equity in earnings of consolidated subsidiaries	62	89	121	97
(Loss) income from continuing operations	83	93	146	116
Income from discontinued operations, net of tax	0	0	0	0
Net (loss) income	83	93	146	116
Net (loss) income attributable to noncontrolling interests	0	0	0	0
Net (loss) income attributable to NCR	83	93	146	116
Total comprehensive income (loss)	46	106	108	140
Less comprehensive income (loss) attributable to noncontrolling interests	0	0	0	0
Comprehensive (loss) income attributable to NCR	46	106	108	140
Non-Guarantor Subsidiaries
Product revenue	306	336	588	673
Service revenue	485	457	951	881
Total revenue	791	793	1,539	1,554
Cost of products	271	272	496	580
Cost of services	326	316	658	618
Selling, general and administrative expenses	131	98	211	193
Research and development expenses	36	16	56	53
Asset Impairment Charges	18		18
Total operating expenses	782	702	1,439	1,444
(Loss) income from operations	9	91	100	110
Interest expense	(3)	(4)	(6)	(5)
Other (expense), net	4	9	2	22
(Loss) income from continuing operations before income taxes	10	96	96	127
Income tax expense (benefit)	(46)	20	(33)	20
Income (loss) from continuing operations before earnings in subsidiaries	56	76	129	107
Equity in earnings of consolidated subsidiaries	0	0	0	0
(Loss) income from continuing operations	56	76	129	107
Income from discontinued operations, net of tax	(1)	0	(1)	0
Net (loss) income	55	76	128	107
Net (loss) income attributable to noncontrolling interests	(1)	0	0	0
Net (loss) income attributable to NCR	56	76	128	107
Total comprehensive income (loss)	10	75	97	118
Less comprehensive income (loss) attributable to noncontrolling interests	(4)	0	(3)	0
Comprehensive (loss) income attributable to NCR	$ 14	$ 75	$ 100	$ 118