Accumulated Other Comprehensive Income (Loss) (AOCI) - Reclassifications Out of AOCI (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Selling, General and Administrative Expense	$ (252)	$ (261)	$ (504)	$ (506)
Research and development expenses	(62)	(65)	(121)	(131)
Income (loss) from continuing operations	88	(144)	126	(88)
Income tax expense	(15)	12	(24)	5
Net income (loss) attributable to NCR common stockholders	76	(157)	100	(149)
Product
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Cost of revenue	(539)	(451)	(992)	(871)
Services
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Cost of revenue	(700)	(683)	(1,372)	(1,360)
Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Selling, General and Administrative Expense	(2)	(1)	(2)	(1)
Research and development expenses		(1)		(1)
Income (loss) from continuing operations	(4)	(3)	(8)	(4)
Income tax expense	1	0	1	1
Net income (loss) attributable to NCR common stockholders	(3)	(3)	(7)	(3)
Reclassification out of Accumulated Other Comprehensive Income [Member] | Product
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Cost of revenue	(2)	(1)	(3)
Reclassification out of Accumulated Other Comprehensive Income [Member] | Services
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Cost of revenue		0	(3)	(2)
Reclassification out of Accumulated Other Comprehensive Income [Member] | Effective Cash Flow Hedge Loss (Gain)
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Selling, General and Administrative Expense	0	0	0	0
Research and development expenses		0		0
Income (loss) from continuing operations	0	1	(1)	1
Reclassification out of Accumulated Other Comprehensive Income [Member] | Effective Cash Flow Hedge Loss (Gain) | Product
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Cost of revenue	0	0	0
Reclassification out of Accumulated Other Comprehensive Income [Member] | Effective Cash Flow Hedge Loss (Gain) | Services
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Cost of revenue		1	(1)	1
Reclassification out of Accumulated Other Comprehensive Income [Member] | Amortization of Prior Service Benefit
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Selling, General and Administrative Expense	(2)	(1)	(2)	(1)
Research and development expenses		(1)		(1)
Income (loss) from continuing operations	(2)	(3)	(4)	(5)
Reclassification out of Accumulated Other Comprehensive Income [Member] | Amortization of Prior Service Benefit | Product
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Cost of revenue	0	0	0
Reclassification out of Accumulated Other Comprehensive Income [Member] | Amortization of Prior Service Benefit | Services
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Cost of revenue		(1)	(2)	$ (3)
Reclassification out of Accumulated Other Comprehensive Income [Member] | Changes in Fair Value of Effective Cash Flow Hedges
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Selling, General and Administrative Expense	0	0	0
Research and development expenses		0
Income (loss) from continuing operations	(2)	(1)	(3)
Reclassification out of Accumulated Other Comprehensive Income [Member] | Changes in Fair Value of Effective Cash Flow Hedges | Product
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Cost of revenue	$ (2)	(1)	(3)
Reclassification out of Accumulated Other Comprehensive Income [Member] | Changes in Fair Value of Effective Cash Flow Hedges | Services
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Cost of revenue		$ 0	$ 0