Retirement Benefits (Details 2)	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate	3.40%	4.40%	3.85%
Rate of increase in future compensation levels	1.00%
Expected long-term rate of return on assets	7.16%	7.52%	7.75%
Pension Benefits [Member] \| Minimum
Defined Benefit Plan Disclosure [Line Items]
Rate of increase in future compensation levels		0.50%	0.50%
Pension Benefits [Member] \| Maximum
Defined Benefit Plan Disclosure [Line Items]
Rate of increase in future compensation levels		1.00%	1.00%
Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Discount rate	3.25%	4.35%	3.80%
Rate of increase in future compensation levels	0.00%	0.00%	0.00%
Expected long-term rate of return on assets	0.00%	4.00%	4.00%

Weighted average rate for present value of future retirement benefits cash flows, used to determine net periodic benefit cost of defined benefit plan.

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- Definition

Weighted average rate of return on plan assets, reflecting average rate of earnings expected on existing plan assets and expected contributions, used to determine net periodic benefit cost of defined benefit plan.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (k)(3)
-URI http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=118255775&loc=d3e2919-114920

+ Details

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- Definition

Weighted average rate of compensation increase used to determine net periodic benefit cost of defined benefit plan. Plan includes, but is not limited to, pay-related defined benefit plan.

+ References

+ Details

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

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