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Retirement Benefit Plans - Asset Allocation Ranges of Defined Benefit Plan Investments (Details) | 12 Months Ended |
--- | --- | ---
Sep. 30, 2016 | Sep. 30, 2015
Asset Allocation Range provides flexibility for the Plan's investments |  |
Total | 100.00% | 100.00%
U.S. equities |  |
Asset Allocation Range provides flexibility for the Plan's investments |  |
Total | 50.00% | 50.00%
Asset Allocations Range Minimum | 30.00% |
Asset Allocations Range Maximum | 70.00% |
Non-U.S. equities |  |
Asset Allocation Range provides flexibility for the Plan's investments |  |
Total | 7.00% | 8.00%
Asset Allocations Range Minimum | 0.00% |
Asset Allocations Range Maximum | 20.00% |
U.S. debt securities |  |
Asset Allocation Range provides flexibility for the Plan's investments |  |
Total | 41.00% | 40.00%
Asset Allocations Range Minimum | 20.00% |
Asset Allocations Range Maximum | 70.00% |
Non-U.S. debt securities |  |
Asset Allocation Range provides flexibility for the Plan's investments |  |
Total | 0.00% | 0.00%
Asset Allocations Range Minimum | 0.00% |
Asset Allocations Range Maximum | 10.00% |
Other securities |  |
Asset Allocation Range provides flexibility for the Plan's investments |  |
Total | 2.00% | 2.00%
Asset Allocations Range Minimum | 0.00% |
Asset Allocations Range Maximum | 60.00% |

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