Income Taxes Valuation Allowance, Additional Details (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2013	Sep. 30, 2016
Income Tax Disclosure [Abstract]
Acquisition of businesses					$ 2,400
Valuation Allowance, Deferred Tax Asset, Increase, Amount	$ 0	$ 0	$ 34	$ 21

Total of allowances and reserves, the valuation and qualifying accounts that are either netted against the cost of an asset (in order to value it at its carrying value) or that reflect a liability established to represent expected future costs, acquired in a business combination.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 4
-Subparagraph (SX 210.12-09)
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e24092-122690

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Balance Type:	credit
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