Reportable Segments - Revenues from External Customers and Long-Lived Assets (Details) - USD ($) $ in Millions		3 Months Ended								12 Months Ended
		Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2015		Sep. 30, 2014	Sep. 30, 2013
Revenues from External Customers and Long-Lived Assets
Assets		$ 6,862				$ 7,202				$ 6,862		$ 7,202
Revenue		1,008	$ 999	$ 995	$ 1,079	1,126	$ 1,054	$ 1,060	$ 1,131	4,081	[1]	4,371	$ 4,578
Long-Lived Assets	[2]	282				281				282		281
U.S.
Revenues from External Customers and Long-Lived Assets
Revenue										2,203	[1]	2,267	2,430
Long-Lived Assets	[2]	180				162				180		162
International
Revenues from External Customers and Long-Lived Assets
Revenue										1,878	[1]	2,104	2,148
Long-Lived Assets	[2]	102				119				102		119
Total EMEA
Revenues from External Customers and Long-Lived Assets
Revenue										1,073	[1]	1,234	1,239
Long-Lived Assets	[2]	72				81				72		81
APAC - Asia Pacific
Revenues from External Customers and Long-Lived Assets
Revenue										425	[1]	445	457
Long-Lived Assets	[2]	18				24				18		24
Americas International - Canada and Latin America
Revenues from External Customers and Long-Lived Assets
Revenue										380	[1]	425	$ 452
Long-Lived Assets	[2]	$ 12				$ 14				$ 12		$ 14

[1] (1)Revenue is attributed to geographic areas based on the location of cust

[2] Represents property, plant and equipment, net.