Income Taxes - Unrecognized Tax Benefit (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Gross unrecognized tax benefits - January 1	$ 248	$ 277	$ 256
Increases related to tax positions from prior years	17	34	33
Decreases related to tax positions from prior years	(37)	(50)	(33)
Increases related to tax provisions taken during the current year	35	43	40
Settlements with tax authorities	(33)	(14)	(2)
Lapses of statutes of limitation	(21)	(42)	(17)
Total Gross unrecognized tax benefits - December 31	209	248	277
Total amount of gross unrecognized tax benefits that would affect NCR's effective tax rate if realized	109
Recognized interest and penalties expense (benefit) associated with uncertain tax positions	(4)	(1)	$ (8)
Interest and penalties accrued associated with uncertain tax positions	46	$ 54
Undistributed earnings of foreign subsidiaries	2,400
Minimum [Member]
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Significant change in unrecognized tax benefits is reasonably possible, estimated range of change, upper bound	10
Maximum [Member]
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Significant change in unrecognized tax benefits is reasonably possible, estimated range of change, upper bound	$ 15