Quarterly Information (unaudited) Statement of Operations (Details) - USD ($)	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Quarterly Financial Information Disclosure [Abstract]
Revenues	$ 1,886,000,000	$ 1,783,000,000	$ 1,710,000,000	$ 1,536,000,000	$ 1,801,000,000	$ 1,550,000,000	$ 1,537,000,000	$ 1,517,000,000	$ 6,915,000,000	$ 6,405,000,000	$ 6,516,000,000
Gross Profit	532,000,000	507,000,000	471,000,000	411,000,000	442,000,000	410,000,000	403,000,000	420,000,000
Income (loss) from operations	182,000,000	172,000,000	157,000,000	100,000,000	63,000,000	125,000,000	(106,000,000)	109,000,000	611,000,000	191,000,000	691,000,000
Income from continuing operations	384,000,000	105,000,000	88,000,000	37,000,000	(33,000,000)	85,000,000	(143,000,000)	55,000,000	614,000,000	(36,000,000)	237,000,000
Income (loss) from discontinued operations, net of tax	(35,000,000)	(15,000,000)	0	0	(14,000,000)	(1,000,000)	(2,000,000)	(35,000,000)	(50,000,000)	(52,000,000)	(5,000,000)
Net income (loss) attributable to NCR	$ 343,000,000	$ 11,000,000	$ 76,000,000	$ 24,000,000	$ (60,000,000)	$ 72,000,000	$ (157,000,000)	$ 8,000,000	$ 564,000,000	$ (88,000,000)	$ 232,000,000
From continuing operations (in dollars per share)	$ 2.96	$ 0.21	$ 0.63	$ 0.20	$ (0.39)	$ 0.62	$ (1.31)	$ 0.36	$ 4.13	$ (0.72)	$ 1.05
From continuing operations (in dollars per share)	2.67	0.21	0.58	0.20	(0.39)	0.57	(1.31)	0.35	3.71	(0.72)	1.01
Net income per common share:
Basic (in dollars per share)	2.69	0.09	0.63	0.20	(0.51)	0.61	(1.33)	0.07	3.72	(1.16)	1.01
Diluted (in dollars per share)	$ 2.43	$ 0.09	$ 0.58	$ 0.20	$ (0.51)	$ 0.56	$ (1.33)	$ 0.06	$ 3.36	$ (1.16)	$ 0.97