Stock-Based Compensation - Stock Grants (Details) - shares	9 Months Ended
Jun. 30, 2017	Jun. 30, 2016
Board of Director Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)	43,019	85,091
Board of Director Units, Compensation Related Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)	28,065	55,380
Award vesting period (in years)	1 year
Board of Director Units, Deferred Annual Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)	13,065,000	25,560,000
Board of Director Units, Deferred Quarterly Dividends
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)	1,889,000	4,151,000

Period which an employee's right to exercise an award is no longer contingent on satisfaction of either a service condition, market condition or a performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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- Definition

The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(2)(iii)(1)
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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