Retirement Benefits (Plan Assets Target Allocation) (Details) - Defined Benefit Pension Plan	Sep. 30, 2019	Sep. 30, 2018
U.S.
Defined Benefit Plan Disclosure [Line Items]
Actual allocation (percent)	100.00%	100.00%
U.S. \| Equity securities
Defined Benefit Plan Disclosure [Line Items]
Target allocation (percent)	39.00%
Actual allocation (percent)	38.00%	41.00%
U.S. \| Debt securities
Defined Benefit Plan Disclosure [Line Items]
Target allocation (percent)	51.00%
Actual allocation (percent)	56.00%	50.00%
U.S. \| Real estate/other
Defined Benefit Plan Disclosure [Line Items]
Actual allocation (percent)	6.00%	8.00%
U.S. \| Cash
Defined Benefit Plan Disclosure [Line Items]
Actual allocation (percent)	0.00%	1.00%
U.S. \| Minimum \| Equity securities
Defined Benefit Plan Disclosure [Line Items]
Target allocation (percent)	43.00%
U.S. \| Minimum \| Debt securities
Defined Benefit Plan Disclosure [Line Items]
Target allocation (percent)	34.00%
U.S. \| Minimum \| Real estate/other
Defined Benefit Plan Disclosure [Line Items]
Target allocation (percent)	0.00%
U.S. \| Minimum \| Cash
Defined Benefit Plan Disclosure [Line Items]
Target allocation (percent)	0.00%
U.S. \| Maximum \| Equity securities
Defined Benefit Plan Disclosure [Line Items]
Target allocation (percent)	58.00%
U.S. \| Maximum \| Debt securities
Defined Benefit Plan Disclosure [Line Items]
Target allocation (percent)	49.00%
U.S. \| Maximum \| Real estate/other
Defined Benefit Plan Disclosure [Line Items]
Target allocation (percent)	10.00%
U.S. \| Maximum \| Cash
Defined Benefit Plan Disclosure [Line Items]
Target allocation (percent)	0.00%
International
Defined Benefit Plan Disclosure [Line Items]
Actual allocation (percent)	100.00%	100.00%
International \| Equity securities
Defined Benefit Plan Disclosure [Line Items]
Target allocation (percent)	49.00%
Actual allocation (percent)	42.00%	46.00%
International \| Debt securities
Defined Benefit Plan Disclosure [Line Items]
Target allocation (percent)	61.00%
Actual allocation (percent)	57.00%	53.00%
International \| Real estate/other
Defined Benefit Plan Disclosure [Line Items]
Target allocation (percent)	0.00%
Actual allocation (percent)	0.00%	0.00%
International \| Cash
Defined Benefit Plan Disclosure [Line Items]
Actual allocation (percent)	1.00%	1.00%
International \| Minimum \| Real estate/other
Defined Benefit Plan Disclosure [Line Items]
Target allocation (percent)	0.00%
International \| Minimum \| Cash
Defined Benefit Plan Disclosure [Line Items]
Target allocation (percent)	0.00%
International \| Maximum \| Cash
Defined Benefit Plan Disclosure [Line Items]
Target allocation (percent)	0.00%

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No definition available.

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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=118257860&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=118255775&loc=d3e1928-114920

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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=118255775&loc=d3e1928-114920

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