Earnings Per Share - Basic Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Earnings Per Share [Abstract]
Income (loss) from continuing operations	$ 107	$ 102	$ 215	$ (202)
Loss from discontinued operations, net of tax	(2)	(4)	(2)	(4)
Net income (loss) attributable to NCR	105	98	213	(206)
Series A convertible preferred stock dividends	(13)	0	(37)	0
Net income (loss) attributable to NCR common stockholders	$ 92	$ 98	$ 176	$ (206)
Weighted Average Number of Shares Outstanding, Diluted [Abstract]
Weighted average outstanding shares of common stock (in shares)	123.9	169.8	126.0	169.5
Earnings Per Share, Basic [Abstract]
Basic earnings from continuing operations (in dollars per share)	$ 0.76	$ 0.60	$ 1.41	$ (1.19)
Basic earnings from discontinued operations (in dollars per share)	(0.02)	(0.02)	(0.01)	(0.03)
Basic (in dollars per share)	$ 0.74	$ 0.58	$ 1.40	$ (1.22)