Condensed Consolidated Statements of Operations (Unaudited) - USD ($) shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Income Statement [Abstract]
Product revenue	$ 618	$ 676	$ 1,172	$ 1,224
Service revenue	975	944	1,899	1,840
Total revenue	1,593	1,620	3,071	3,064
Cost of products	478	517	902	959
Cost of services	652	657	1,293	1,279
Selling, general and administrative expenses	227	229	456	453
Research and development expenses	58	50	125	103
Restructuring-related charges	0	4	0	6
Total operating expenses	1,415	1,457	2,776	2,800
Income from operations	178	163	295	264
Interest expense	(41)	(43)	(80)	(89)
Other (expense), net	(7)	(15)	(14)	(25)
Income from continuing operations before income taxes	130	105	201	150
Income tax expense	33	31	47	44
Income from continuing operations	97	74	154	106
Income from discontinued operations, net of tax	(5)	0	(5)	0
Net income	102	74	159	106
Net loss attributable to noncontrolling interests	0	(2)	0	(2)
Net income attributable to NCR	102	76	159	108
Amounts attributable to NCR common stockholders:
Income from continuing operations	97	76	154	108
Series A convertible preferred stock dividends	(12)	(13)	(24)	(24)
Deemed dividend on modification of Series A convertible preferred stock	0	0	(4)	0
Deemed dividend on preferred stock redemption	0	0	(58)	0
Income from continuing operations attributable to NCR common stockholders	85	63	68	84
Income from discontinued operations, net of tax	(5)	0	(5)	0
Net income attributable to NCR common stockholders	$ 90	$ 63	$ 73	$ 84
Income per common share from continuing operations
Basic earnings from continuing operations (in dollars per share)	$ 0.70	$ 0.51	$ 0.56	$ 0.66
Income (Loss) from Continuing Operations, Per Diluted Share	0.64	0.49	0.53	0.65
Net income per common share
Basic (in dollars per share)	0.74	0.51	0.60	0.66
Diluted (in dollars per share)	$ 0.67	$ 0.49	$ 0.57	$ 0.65
Weighted average common shares outstanding
Weighted average outstanding shares of common stock (in shares)	121.4	123.8	122.1	127.1
Diluted (in shares)	152.7	154.5	127.2	129.6