Description of Business and Significant Accounting Policies - Earnings Per Share (Diluted) (Details) - USD ($) $ / shares in Units, shares in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Earnings Per Share Reconciliation [Abstract]
Income from continuing operations	$ 384,000,000	$ 105,000,000	$ 88,000,000	$ 37,000,000	$ (33,000,000)	$ 85,000,000	$ (143,000,000)	$ 55,000,000	$ 614,000,000	$ (36,000,000)	$ 237,000,000
Preferred Stock Dividends Income Statement Impact Included in Diluted Earnings Per Share From Continuing Operations									76,000,000
Net Income (Loss) from Continuing Operations Available to Common Shareholders, Diluted									538,000,000	(85,000,000)	128,000,000
Income (loss) from discontinued operations, net of tax	$ (35,000,000)	$ (15,000,000)	$ 0	$ 0	$ (14,000,000)	$ (1,000,000)	$ (2,000,000)	$ (35,000,000)	(50,000,000)	(52,000,000)	(5,000,000)
Net income (loss) attributable to NCR common stockholders									$ 488,000,000	$ (137,000,000)	$ 123,000,000
Weighted average outstanding shares of common stock									122.1	118.4	121.9
Incremental Common Shares Attributable to Dilutive Effect of Conversion of Preferred Stock									19.5	0.0	0.0
Dilutive effect of employee stock options and restricted stock									3.6	0.0	5.1
Weighted Average Number of Shares Outstanding, Diluted									145.2	118.4	127.0
Diluted earnings (loss) per share [Abstract]
Diluted (in dollars per share)	$ 2.67	$ 0.21	$ 0.58	$ 0.20	$ (0.39)	$ 0.57	$ (1.31)	$ 0.35	$ 3.71	$ (0.72)	$ 1.01
From discontinued operations (in dollars per share)									(0.35)	(0.44)	(0.04)
Diluted (in dollars per share)	$ 2.43	$ 0.09	$ 0.58	$ 0.20	$ (0.51)	$ 0.56	$ (1.33)	$ 0.06	$ 3.36	$ (1.16)	$ 0.97
Series A Preferred Stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount									5.7	28.3	27.4
Restricted Stock Units (RSUs) and Stock Options [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount									4.3	5.6
Restricted Stock Units (RSUs) [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount											0.8