Condensed Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 88	$ (146)	$ 126	$ (125)
Currency translation adjustments
Currency translation gains (losses)	(8)	(49)	11	(30)
Derivatives
Unrealized gains on derivatives	0	9	1	4
Gains on derivatives recognized during the period	(2)	(1)	(3)	0
Less income tax provision	1	0	1	0
Employee benefit plans
Amortization of prior service benefit	(2)	(3)	(4)	(5)
Amortization of actuarial (losses) gains	0	1	(1)	1
Less income tax benefit	0	0	0	1
Other comprehensive income (loss)	(11)	(43)	5	(29)
Total comprehensive income (loss)	77	(189)	131	(154)
Less comprehensive income attributable to noncontrolling interests:
Net income (loss)	0	(1)	1	0
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax, Portion Attributable to Noncontrolling Interest	0	(3)	0	(3)
Amounts attributable to noncontrolling interests	0	(4)	1	(3)
Comprehensive income (loss) attributable to NCR	$ 77	$ (185)	$ 130	$ (151)