Earnings Per Share - Basic Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Earnings Per Share [Abstract]
Income (loss) from continuing operations	$ 76	$ (344)	$ 108	$ (304)
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent	0	0	0	0
Net income (loss) attributable to NCR	76	(344)	108	(304)
Series A convertible preferred stock dividends	(13)	0	(24)	0
Net income (loss) attributable to NCR common stockholders	$ 63	$ (344)	$ 84	$ (304)
Weighted Average Number of Shares Outstanding, Diluted [Abstract]
Weighted average outstanding shares of common stock (in shares)	123.8	169.6	127.1	169.3
Earnings Per Share, Basic [Abstract]
Basic earnings from continuing operations (in dollars per share)	$ 0.51	$ (2.03)	$ 0.66	$ (1.80)
Basic earnings from discontinued operations (in dollars per share)	0.00	0.00	0.00	0.00
Basic (in dollars per share)	$ 0.51	$ (2.03)	$ 0.66	$ (1.80)