Earnings Per Share - Basic Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Numerator:
Income (loss) from continuing operations	$ 64,000,000	$ 88,000,000	$ 87,000,000	$ 125,000,000
Dividends on convertible preferred stock	(7,000,000)	(12,000,000)	(13,000,000)	(25,000,000)
Income from continuing operations attributable to NCR common stockholders	57,000,000	76,000,000	74,000,000	100,000,000
Loss from discontinued operations, net of tax	0	0	0	0
Net income (loss) attributable to NCR common stockholders	$ 57,000,000	$ 76,000,000	$ 74,000,000	$ 100,000,000
Denominator:
Weighted average outstanding shares of common stock (in shares)	128.0	120.2	128.0	119.8
Basic earnings per share:
From continuing operations (in dollars per share)	$ 0.45	$ 0.63	$ 0.58	$ 0.83
From discontinued operations (in dollars per share)	0	0	0	0
Total basic earnings (loss) per share (in dollars per share)	$ 0.45	$ 0.63	$ 0.58	$ 0.83