Accumulated Other Comprehensive Income (Loss) (AOCI) Reclassifications (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
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)
Interest expense	(163)	(170)	(173)
Income (loss) from continuing operations	240	287	(150)
Income tax expense	(242)	(92)	(55)
Net income (loss) attributable to NCR common stockholders	123	221	(182)
Reclassification out of Accumulated Other Comprehensive Income
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Cost of products	(1)	(3)	(13)
Cost of services	(7)	(11)	(8)
Selling, general and administrative expenses	(4)	(6)	(6)
Research and development expenses	(2)	(4)	(4)
Interest expense		2	5
Income (loss) from continuing operations	(14)	(22)	(26)
Income tax expense	5	4	8
Net income (loss) attributable to NCR common stockholders	(9)	(18)	(18)
Reclassification out of Accumulated Other Comprehensive Income | Actuarial losses recognized
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Cost of products	0	0	0
Cost of services	(1)	(1)	1
Selling, general and administrative expenses	0	0	1
Research and development expenses	(1)	(1)	0
Interest expense		0	0
Income (loss) from continuing operations	(2)	(2)	2
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	(1)
Cost of services	(6)	(10)	(9)
Selling, general and administrative expenses	(4)	(6)	(7)
Research and development expenses	(1)	(3)	(4)
Interest expense		0	0
Income (loss) from continuing operations	(11)	(19)	(21)
Reclassification out of Accumulated Other Comprehensive Income | Effective Cash Flow Hedges
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Cost of products	(1)	(3)	(12)
Cost of services	0	0	0
Selling, general and administrative expenses	0	0	0
Research and development expenses	0	0	0
Interest expense		2	5
Income (loss) from continuing operations	$ (1)	$ (1)	$ (7)