Other Comprehensive Income (Loss) (Reclassifications out of Accumulated Other Comprehensive Income) (Parenthetical) (Details) - Defined Benefit Pension and Postretirement Plans [Member]	12 Months Ended
Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Condensed Statement Of Income Captions [Line Items]
Loss adjustment expenses	40.00%	40.00%	40.00%
Percentage of other operating expenses	60.00%	60.00%	60.00%

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.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name Regulation S-X (SX)
-Number 210
-Section 12
-Subsection 04
-Paragraph a
-Publisher SEC

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 235
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 3
-Subparagraph (SX 210.12-04(a))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480678/235-10-S99-3

Reference 3: http://www.xbrl.org/2003/role/recommendedDisclosureRef
-Topic 810
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 11
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481231/810-10-45-11

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