Retirement Benefits - Plan Target and Actual Asset Allocation (Details)	Dec. 31, 2023	Dec. 31, 2022
Equity securities \| All Pension Benefit Plans
Defined Benefit Plan Disclosure [Line Items]
Target Mix	26.00%	25.00%
Actual Mix	26.00%	25.00%
Equity securities \| Postretirement Health Care Benefits Plan
Defined Benefit Plan Disclosure [Line Items]
Target Mix	28.00%	28.00%
Actual Mix	28.00%	28.00%
Fixed income securities \| All Pension Benefit Plans
Defined Benefit Plan Disclosure [Line Items]
Target Mix	56.00%	57.00%
Actual Mix	56.00%	56.00%
Fixed income securities \| Postretirement Health Care Benefits Plan
Defined Benefit Plan Disclosure [Line Items]
Target Mix	51.00%	52.00%
Actual Mix	52.00%	52.00%
Cash and other investments \| All Pension Benefit Plans
Defined Benefit Plan Disclosure [Line Items]
Target Mix	18.00%	18.00%
Actual Mix	18.00%	19.00%
Cash and other investments \| Postretirement Health Care Benefits Plan
Defined Benefit Plan Disclosure [Line Items]
Target Mix	21.00%	20.00%
Actual Mix	20.00%	20.00%

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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
-Topic 715
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 17
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480482/715-20-55-17

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 715
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (d)(i)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480506/715-20-50-1

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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
-Topic 715
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (d)(i)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480506/715-20-50-1

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