Segment Information and Concentrations - Revenue and Operating Income By Segments (Details) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2018 USD ($)	Sep. 30, 2017 USD ($)	Sep. 30, 2018 USD ($) segment	Sep. 30, 2017 USD ($)
Segment Reporting Information [Line Items]
Number of Reportable Segments \| segment			3
Product revenue	$ 1,550	$ 1,663	$ 4,604	$ 4,734
Asset impairment charges	0	0	183	0
Income from operations	125	199	128	489
Operating Segments
Segment Reporting Information [Line Items]
Product revenue	1,550	1,663	4,604	4,734
Operating income by segment	161	234	474	604
Segment Reconciling Items
Segment Reporting Information [Line Items]
Transformation and restructuring costs	16	5	98	26
Asset impairment charges	0	0	183	0
Acquisition-related amortization of intangible assets	20	29	64	86
Acquisition-related costs	0	1	1	3
Other adjustments	36	35	346	115
Software \| Operating Segments
Segment Reporting Information [Line Items]
Product revenue	480	476	1,410	1,392
Operating income by segment	127	148	351	399
Services \| Operating Segments
Segment Reporting Information [Line Items]
Product revenue	616	609	1,827	1,754
Operating income by segment	90	88	229	206
Hardware \| Operating Segments
Segment Reporting Information [Line Items]
Product revenue	454	578	1,367	1,588
Operating income by segment	(56)	(2)	(106)	(1)
Software License \| Software \| Operating Segments
Segment Reporting Information [Line Items]
Product revenue	80	79	218	241
Software Maintenance \| Software \| Operating Segments
Segment Reporting Information [Line Items]
Product revenue	92	95	276	278
Cloud \| Software \| Operating Segments
Segment Reporting Information [Line Items]
Product revenue	158	149	468	436
Professional Services \| Software \| Operating Segments
Segment Reporting Information [Line Items]
Product revenue	150	153	448	437
ATM \| Hardware \| Operating Segments
Segment Reporting Information [Line Items]
Product revenue	237	273	612	709
SCO \| Hardware \| Operating Segments
Segment Reporting Information [Line Items]
Product revenue	60	79	236	276
POS \| Hardware \| Operating Segments
Segment Reporting Information [Line Items]
Product revenue	157	221	519	588
IPS \| Hardware \| Operating Segments
Segment Reporting Information [Line Items]
Product revenue	$ 0	$ 5	$ 0	$ 15

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