Accumulated Other Comprehensive Income (Loss) (AOCI) - Reclassifications Out of AOCI (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Selling, General and Administrative Expense	$ (254)	$ (271)	$ (743)	$ (775)
Research and development expenses	(55)	(64)	(169)	(185)
Interest Expense	60	53	167	143
Income (Loss) from Continuing Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest	32	104	120	230
Income tax expense	0	(4)	33	(28)
Net income (loss) attributable to NCR common stockholders	25	11	99	111
Product
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Cost of revenue	(452)	(555)	(1,254)	(1,547)
Service [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Cost of revenue	(710)	(721)	(2,126)	(2,093)
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, Net of Tax, Including Portion Attributable to Noncontrolling Interest	3	(3)	(2)	(11)
Income tax expense	(1)	1	1	2
Net income (loss) attributable to NCR common stockholders	2	(2)	(1)	(9)
Reclassification out of Accumulated Other Comprehensive Income [Member] | Product
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Cost of revenue	3	(2)	(2)	5
Research and development expenses	1
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)	3	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		1	0
Research and development expenses			0
Income (Loss) from Continuing Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest	0	0	(2)	(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
Research and development expenses	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	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)		1	2
Research and development expenses			(1)
Income (Loss) from Continuing Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest	0	(1)	(2)	(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	0
Research and development expenses	1
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
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, Net of Tax, Including Portion Attributable to Noncontrolling Interest	3	(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	3	(2)	(2)	5
Research and development expenses	$ 0
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