Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	0.8	0.5
Stock Repurchased During Period, Shares	8.6
Stock Repurchased During Period, Value	$ 209.0	$ 0.0
Stock Repurchased and Retired During Period, Value	$ 4.0
Stock Repurchased and Retired During Period, Shares	0.1
Income (loss) from continuing operations	$ 32.0	40.0
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent	0.0	0.0
Income (Loss) from Discontinued Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest	0.0	0.0
Net income (loss) attributable to NCR	32.0	40.0
Preferred Stock Dividends, Income Statement Impact	(11.0)	0.0
Net income (loss)	$ 21.0	$ 40.0
Earnings Per Share, Potentially Dilutive Securities	27.7
Weighted Average Number of Shares Outstanding, Diluted [Abstract]
Weighted average outstanding shares of common stock (in shares)	130.4	169.0
Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements	2.3	2.6
Diluted (in shares)	132.7	171.6
Earnings Per Share, Basic [Abstract]
Basic earnings from continuing operations (in dollars per share)	$ 0.16	$ 0.24
Basic earnings from discontinued operations (in dollars per share)	0.00	0.00
Basic (in dollars per share)	0.16	0.24
Earnings Per Share, Diluted [Abstract]
Diluted earnings from continuing operations (in dollars per share)	0.16	0.23
Diluted earnings from discontinued operations (in dollars per share)	0.00	0.00
Diluted (in dollars per share)	$ 0.16	$ 0.23