Retirement Plans Projected Benefit Payments from Plans (Details) $ in Millions	Sep. 30, 2018 USD ($)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Estimated future employer contributions to defined benefit plans in next fiscal year	$ 85
Pension Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
2018	317
2019	304
2020	304
2021	312
2022	316
2023-2027	1,628
Postretirement Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Estimated future employer contributions to defined benefit plans in next fiscal year	15
2018	19
2019	19
2020	19
2021	18
2022	18
2023-2027	$ 74

Amount of benefits for defined benefit plan expected to be paid in five fiscal years after fifth fiscal year following latest fiscal year.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (f)
-URI http://asc.fasb.org/extlink&oid=82843861&loc=d3e1928-114920

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Amount of benefits for defined benefit plan expected to be paid in next fiscal year following latest fiscal year.

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Amount of benefits for defined benefit plan expected to be paid in fifth fiscal year following latest fiscal year.

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Amount of benefits for defined benefit plan expected to be paid in fourth fiscal year following latest fiscal year.

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Amount of benefits for defined benefit plan expected to be paid in second fiscal year following latest fiscal year.

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Amount of contributions expected to be received by defined benefit plan from employer in next fiscal year following latest fiscal year.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (g)
-URI http://asc.fasb.org/extlink&oid=82843861&loc=d3e1928-114920

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