Earnings Per Share - Diluted Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Numerator:
Income (loss) from continuing operations	$ 23	$ 37
Preferred Stock Dividends Income Statement Impact Included in Diluted Earnings Per Share From Continuing Operations	6	13
Preferred Stock Dividends, Income Statement Impact	6	13
Income from continuing operations attributable to NCR common stockholders	17	24
Loss from discontinued operations, net of tax	0	0
Net income attributable to NCR common stockholders	$ 17	$ 24
Weighted average outstanding shares of common stock (in shares)	128.0	119.3
Dilutive effect of restricted stock units (in shares)	2.5	2.9
Denominator (in shares)	130.5	122.2
Diluted earnings per share:
From continuing operations (in dollars per share)	$ 0.13	$ 0.20
From discontinued operations (in dollars per share)	0	0
Total diluted earnings (loss) per share (in dollars per share)	$ 0.13	$ 0.20
Series A Convertible Preferred Stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from diluted per share count (in shares)	13.2	29.2
Restricted Stock Units (RSUs) and Stock Options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from diluted per share count (in shares)	7.8	4.5