Basis of Presentation and Summary of Significant Accounting Policies (Narrative, Recent Financial Accounting Standards) (Details) - USD ($) $ in Millions	Jun. 30, 2017	Sep. 30, 2016	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2014
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Valuation Allowances and Reserves, Balance	$ 494		$ 541	$ 455	$ 429
Long-term Debt | Accounting Standards Update 2015-03 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Debt Issuance Costs, Net		$ 29
Other Assets | Accounting Standards Update 2015-03 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Debt Issuance Costs, Net		$ (29)