Accumulated Other Comprehensive Income (Loss) (AOCI) - Reclassifications (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Cost of products	$ (420)	$ (424)
Cost of services	(677)	(642)
Income from continuing operations	56	57
Income tax expense	(7)	(14)
Net income (loss) attributable to NCR common stockholders	8	(17)
Reclassification out of Accumulated Other Comprehensive Income
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Cost of products	1	2
Cost of services	(2)	(3)
Income from continuing operations	(1)	(5)
Income tax expense	1	1
Net income (loss) attributable to NCR common stockholders	0	(4)
Reclassification out of Accumulated Other Comprehensive Income | Actuarial losses recognized
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Cost of products		0
Cost of services		(1)
Income from continuing operations		(1)
Reclassification out of Accumulated Other Comprehensive Income | Amortization of prior service benefit
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Cost of products	0	0
Cost of services	(2)	(2)
Income from continuing operations	(2)	(2)
Reclassification out of Accumulated Other Comprehensive Income | Effective Cash Flow Hedges
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Cost of products	1	2
Cost of services	0	0
Income from continuing operations	$ 1	$ (2)