Description of Business and Significant Accounting Policies Description of Business and Significant Accounting Policies - Earnings Per Share (Basic) (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 [Abstract]
Income (loss) 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									110,000,000	49,000,000	109,000,000
Preferred Stock Dividends Income Statement Impact Included in Diluted Earnings Per Share From Continuing Operations									76,000,000
Income (loss) from continuing operations attributable to common stockholders									504,000,000	(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									$ 454,000,000	$ (137,000,000)	$ 123,000,000
Basic (in shares)									122.1	118.4	121.9
Basic (in dollars per share)	$ 2.96	$ 0.21	$ 0.63	$ 0.20	$ (0.39)	$ 0.62	$ (1.31)	$ 0.36	$ 4.13	$ (0.72)	$ 1.05
Income (Loss) from Discontinued Operations and Disposal of Discontinued Operations, Net of Tax, Per Basic Share									(0.41)	(0.44)	(0.04)
Basic (in dollars per share)	$ 2.69	$ 0.09	$ 0.63	$ 0.20	$ (0.51)	$ 0.61	$ (1.33)	$ 0.07	$ 3.72	$ (1.16)	$ 1.01