Consolidated Statements of Operations (USD $) In Millions, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Statement [Abstract]
Product revenue	$ 2,892	$ 2,912	$ 2,854
Service revenue	3,699	3,211	2,876
Total revenue	6,591	6,123	5,730
Cost of products	2,153	2,152	2,144
Cost of services	2,706	2,231	1,941
Selling, general and administrative expenses	1,012	871	742
Research and development expenses	263	203	155
Restructuring-related charges	104	0	0
Total operating expenses	6,238	5,457	4,982
Income from operations	353	666	748
Interest expense	(181)	(103)	(42)
Other (expense), net	(35)	(9)	(8)
Income from continuing operations before income taxes	137	554	698
Income tax (benefit) expense	(48)	98	223
Income from continuing operations	185	456	475
Income (loss) from discontinued operations, net of tax	10	(9)	6
Net income	195	447	481
Net income attributable to noncontrolling interests	4	4	0
Net income attributable to NCR	191	443	481
Amounts attributable to NCR common stockholders:
Income from continuing operations	181	452	475
Income (loss) from discontinued operations, net of tax	10	(9)	6
Net income	$ 191	$ 443	$ 481
Income per share attributable to NCR common stockholders:
Basic (in dollars per share)	$ 1.08	$ 2.73	$ 2.98
Diluted (in dollars per share)	$ 1.06	$ 2.67	$ 2.90
Net income per common share
Basic (in dollars per share)	$ 1.14	$ 2.68	$ 3.02
Total diluted earnings (loss) per share	$ 1.12	$ 2.62	$ 2.94
Weighted average common shares outstanding
Basic (in shares)	167.9	165.4	159.3
Diluted (in shares)	171.2	169.3	163.8