Condensed Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 86	$ 119	$ (39)	$ 278
Currency translation adjustments
Currency translation (losses) gains	(13)	6	(43)	35
Derivatives
Unrealized gains (losses) on derivatives	1	(5)	5	(15)
(Losses) gains on derivatives recognized during the period	(2)	1	(2)	(2)
Less income tax (benefit) provision	(1)	0	(1)	3
Employee benefit plans
Amortization of prior service benefit	(2)	(1)	(7)	(6)
Amortization of actuarial loss (benefit)	0	(1)	1	(2)
Less income tax provision	0	0	1	2
Other comprehensive (loss) income	(17)	0	(46)	15
Total comprehensive income (loss)	69	119	(85)	293
Less comprehensive income (loss) attributable to noncontrolling interests:
Net income	2	1	2	1
Currency translation gains (losses)	1	(2)	(2)	(2)
Amounts attributable to noncontrolling interests	3	(1)	0	(1)
Comprehensive income (loss) attributable to NCR	$ 66	$ 120	$ (85)	$ 294