Employee Retirement Plans - Pension Plans Assets (Details) - Pension Benefits - U.S.	Sep. 30, 2021	Sep. 30, 2020
Defined Benefit Plans and Other Postretirement Benefit Plans
Actual	100.00%	100.00%
Target Asset Allocation	100.00%	100.00%
Target allocation range	5.00%
U.S. equities
Defined Benefit Plans and Other Postretirement Benefit Plans
Actual	22.20%	26.50%
Target Asset Allocation	25.30%	29.00%
Non-U.S. equities
Defined Benefit Plans and Other Postretirement Benefit Plans
Actual	21.70%	25.00%
Target Asset Allocation	21.40%	24.50%
Global equities
Defined Benefit Plans and Other Postretirement Benefit Plans
Actual	16.00%	12.30%
Target Asset Allocation	13.10%	11.50%
Equity investments
Defined Benefit Plans and Other Postretirement Benefit Plans
Actual	59.90%	63.80%
Target Asset Allocation	59.80%	65.00%
Fixed income funds & cash equivalents
Defined Benefit Plans and Other Postretirement Benefit Plans
Actual	36.40%	36.20%
Target Asset Allocation	34.40%	35.00%
Alternative investments
Defined Benefit Plans and Other Postretirement Benefit Plans
Actual	3.70%	0.00%
Target Asset Allocation	5.80%	0.00%

Defined Benefit Plan, Plan Assets, Target Allocation Range, Percentage

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- Definition

Percentage of target investment allocation to total plan assets. Includes, but is not limited to, percentage on weighted-average basis if more than one plan.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 55
-Paragraph 17
-URI http://asc.fasb.org/extlink&oid=123450688&loc=d3e4179-114921

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (d)(i)
-URI http://asc.fasb.org/extlink&oid=123447040&loc=d3e1928-114920

+ Details

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- Definition

Percentage of actual investment allocation to total plan assets. Includes, but is not limited to, percentage on weighted-average basis if more than one plan.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (d)(i)
-URI http://asc.fasb.org/extlink&oid=123447040&loc=d3e1928-114920

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+ References

No definition available.

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