Schedule II (details) - Guarantees Footnote (details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Guarantor obligations
Amount of certain debt obligations of TPC that are unconditionally guaranteed by The Travelers Companies, Inc.	$ 700
7.75% Senior notes due April 15, 2026 [Member]
Guarantor obligations
Amount of certain debt obligations of TPC that are unconditionally guaranteed by The Travelers Companies, Inc.	$ 200
Interest rate (percent)	7.75%	7.75%
6.375% Senior notes due March 15, 2033 [Member]
Guarantor obligations
Amount of certain debt obligations of TPC that are unconditionally guaranteed by The Travelers Companies, Inc.	$ 500
Interest rate (percent)	6.375%	6.375%
Indemnifications related to the sale of businesses [Member]
Guarantor obligations
Maximum amount of contingent obligation	$ 391
Amount recognized on balance sheet for contingent obligation	2
Indemnifications related to the sale of businesses [Member] \| Travelers [Member]
Guarantor obligations
Maximum amount of contingent obligation	44
Amount recognized on balance sheet for contingent obligation	2
Guarantees on payment of principal, premiums and interest on certain debt obligations [Member] \| Travelers [Member] \| 7.75% Senior notes due April 15, 2026 [Member]
Guarantor obligations
Amount of certain debt obligations of TPC that are unconditionally guaranteed by The Travelers Companies, Inc.	$ 200
Interest rate (percent)	7.75%
Guarantees on payment of principal, premiums and interest on certain debt obligations [Member] \| Travelers [Member] \| 6.375% Senior notes due March 15, 2033 [Member]
Guarantor obligations
Amount of certain debt obligations of TPC that are unconditionally guaranteed by The Travelers Companies, Inc.	$ 500
Interest rate (percent)	6.375%

Amount of certain debt obligations of TPC that are unconditionally guaranteed by The Travelers Companies, Inc.

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- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(1))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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- Definition

The current carrying amount of the liability for the freestanding or embedded guarantor's obligations under the guarantee or each group of similar guarantees.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 460
-SubTopic 10
-Section 50
-Paragraph 4
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=6851643&loc=d3e12069-110248

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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.

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- Definition

Maximum potential amount of future payments (undiscounted) the guarantor could be required to make under the guarantee or each group of similar guarantees before reduction for potential recoveries under recourse or collateralization provisions.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 460
-SubTopic 10
-Section 50
-Paragraph 4
-Subparagraph (b)(1)
-URI http://asc.fasb.org/extlink&oid=6851643&loc=d3e12069-110248

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