Goodwill and Acquired Intangible Assets - Gross Carrying Amount and Accumulated Amortization for Teradata Acquired Intangible Assets (Detail) - USD ($) $ in Millions	6 Months Ended	12 Months Ended
	Jun. 30, 2015	Dec. 31, 2014
Acquired Finite-Lived Intangible Assets
Gross Carrying Amount	$ 269	$ 269
Accumulated Amortization and Currency Translation Adjustments	(156)	(133)
Intellectual property/developed technology
Acquired Finite-Lived Intangible Assets
Gross Carrying Amount	186	186
Accumulated Amortization and Currency Translation Adjustments	(112)	(95)
Customer relationships
Acquired Finite-Lived Intangible Assets
Gross Carrying Amount	77	77
Accumulated Amortization and Currency Translation Adjustments	$ (41)	$ (35)
Trademarks/trade names
Acquired Finite-Lived Intangible Assets
Amortization Life (in Years)	5 years	5 years
Gross Carrying Amount	$ 1	$ 1
Accumulated Amortization and Currency Translation Adjustments	$ (1)	$ (1)
In-process research and development
Acquired Finite-Lived Intangible Assets
Amortization Life (in Years)	5 years	5 years
Gross Carrying Amount	$ 5	$ 5
Accumulated Amortization and Currency Translation Adjustments	$ (2)	$ (2)
Minimum | Intellectual property/developed technology
Acquired Finite-Lived Intangible Assets
Amortization Life (in Years)	1 year	1 year
Minimum | Customer relationships
Acquired Finite-Lived Intangible Assets
Amortization Life (in Years)	3 years	3 years
Maximum | Intellectual property/developed technology
Acquired Finite-Lived Intangible Assets
Amortization Life (in Years)	7 years	7 years
Maximum | Customer relationships
Acquired Finite-Lived Intangible Assets
Amortization Life (in Years)	10 years	10 years