Shareholders' Equity Stockholders Equity (Details) - USD ($) shares in Millions, $ in Millions		3 Months Ended		9 Months Ended
	Jan. 01, 2018	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Total stockholders’ equity	$ 737	$ 448		$ 448		$ 722
Cumulative Effect on Retained Earnings, Net of Tax	15
Net Income (Loss), Including Portion Attributable to Nonredeemable Noncontrolling Interest				(40)
Other comprehensive income, Attributable to NCR				(44)
Stock Repurchased and Retired During Period, Value				(210)
Dividends, Preferred Stock				(36)
Employee stock compensation expense		15	$ 19	55	$ 60
Tax Withholding for Share-based Compensation				(30)
Proceeds from employee stock plans				$ 16	$ 11
Stock Repurchased and Retired During Period, Shares				6.1
Parent [Member]
Total stockholders’ equity	734	444		$ 444		719
Cumulative Effect on Retained Earnings, Net of Tax	15
Net Income (Loss), Including Portion Attributable to Nonredeemable Noncontrolling Interest				(41)
Other comprehensive income, Attributable to NCR				(44)
Stock Repurchased and Retired During Period, Value				(210)
Dividends, Preferred Stock				(36)
Employee stock compensation expense				55
Tax Withholding for Share-based Compensation				(30)
Proceeds from employee stock plans				16
Noncontrolling Interest [Member]
Total stockholders’ equity	3	$ 4		4		$ 3
Cumulative Effect on Retained Earnings, Net of Tax	$ 0
Net Income (Loss), Including Portion Attributable to Nonredeemable Noncontrolling Interest				1
Other comprehensive income, Attributable to NCR				0
Stock Repurchased and Retired During Period, Value				0
Dividends, Preferred Stock				0
Employee stock compensation expense				0
Tax Withholding for Share-based Compensation				0
Proceeds from employee stock plans				$ 0