Accumulated Other Comprehensive Income (Loss) (AOCI) - Reclassifications Out of AOCI (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Selling, General and Administrative Expense	$ (271)	$ (226)	$ (775)	$ (732)
Research and development expenses	(64)	(59)	(185)	(190)
Income (loss) from continuing operations	104	87	230	(1)
Income tax expense	(4)	15	(28)	20
Net income (loss) attributable to NCR common stockholders	11	72	111	(77)
Product
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Cost of revenue	(555)	(473)	(1,547)	(1,344)
Service [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Cost of revenue	(721)	(667)	(2,093)	(2,027)
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		(1)	(2)	(2)
Research and development expenses		1
Income (loss) from continuing operations	(3)	(4)	(11)	(8)
Income tax expense	1	0	2	1
Net income (loss) attributable to NCR common stockholders	(2)	(4)	(9)	(7)
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)	(2)	(5)	(2)
Reclassification out of Accumulated Other Comprehensive Income [Member] | Service [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Cost of revenue	(1)	(2)	(4)	(4)
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
Research and development expenses		0
Income (loss) from continuing operations	0	0	(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	0
Reclassification out of Accumulated Other Comprehensive Income [Member] | Effective Cash Flow Hedge Loss (Gain) | Service [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Cost of revenue	0	0	(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		(1)	(2)	(2)
Research and development expenses		1
Income (loss) from continuing operations	(1)	(2)	(5)	(7)
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	0
Reclassification out of Accumulated Other Comprehensive Income [Member] | Amortization of Prior Service Benefit | Service [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Cost of revenue	(1)	(2)	(3)	(5)
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
Research and development expenses		0
Income (loss) from continuing operations	(2)	(2)	(5)
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)	(2)	(5)	(2)
Selling, General and Administrative Expense				0
Income (loss) from continuing operations				(2)
Reclassification out of Accumulated Other Comprehensive Income [Member] | Changes in Fair Value of Effective Cash Flow Hedges | Service [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Cost of revenue	$ 0	$ 0	$ 0	$ 0