Statutory Accounting Information (Schedule Of Statutory Net Income And Statutory Surplus (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
The Cincinnati Insurance Company
Statutory Accounting Practices
SAP net income (loss)	$ 466	$ 558	$ 626
Capital and surplus	5,838	5,620
The Cincinnati Casualty Company
Statutory Accounting Practices
SAP net income (loss)	14	13	16
Capital and surplus	456	437
The Cincinnati Indemnity Company
Statutory Accounting Practices
SAP net income (loss)	3	3	5
Capital and surplus	115	111
The Cincinnati Specialty Underwriters Insurance Company
Statutory Accounting Practices
SAP net income (loss)	42	62	69
Capital and surplus	528	526
The Cincinnati Life Insurance Company
Statutory Accounting Practices
SAP net income (loss)	27	19	$ 0
Capital and surplus	$ 241	$ 204

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.

No definition available.

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- Definition

The amount of statutory capital and surplus (stockholders' equity) as of the balance sheet date using prescribed or permitted statutory accounting practices (rather than GAAP, if different) of the state or country.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(23)(c))
-URI http://asc.fasb.org/extlink&oid=120400017&loc=d3e572229-122910

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 505
-Section 50
-Paragraph 1
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=6486098&loc=d3e24708-158529

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- Definition

Amount of net income for the period determined using accounting principles prescribed or permitted by insurance regulators.

+ References

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