Retirement Benefits (Narrative) (Details) - USD ($) $ in Millions	1 Months Ended	3 Months Ended
Apr. 30, 2020	Mar. 31, 2020
Defined Benefit Plan Disclosure [Line Items]
Pension contributions		$ 15
Payment for additional discretionary funding		0
Estimated future employer contributions in current fiscal year		$ 15
Subsequent Event
Defined Benefit Plan Disclosure [Line Items]
Estimated future discretionary employer contributions	$ 200

Payment for Pension Benefits, Additional Discretionary Funding

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- Definition

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+ References

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- Definition

Amount of contributions expected to be received by defined benefit plan from employer in fiscal year. Excludes contributions paid by employer in current fiscal year.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 6
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=118255775&loc=d3e2709-114920

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- Definition

Amount of discretionary contributions made by an employer to a defined contribution plan.

+ References

No definition available.

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- Definition

Amount of cash outflow for pension benefit. Includes, but is not limited to, employer contribution to fund plan asset and payment to retiree. Excludes other postretirement benefit.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 25
-Subparagraph (g)
-URI http://asc.fasb.org/extlink&oid=118932676&loc=d3e3536-108585

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