Schedule II (details) - Guarantees Footnote (details) (USD $) In Millions, unless otherwise specified								12 Months Ended
	Dec. 31, 2012	Dec. 31, 2012 5.00% Senior notes due March 15, 2013 [Member]	Dec. 31, 2011 5.00% Senior notes due March 15, 2013 [Member]	Dec. 31, 2012 7.75% Senior notes due April 15, 2026 [Member]	Dec. 31, 2011 7.75% Senior notes due April 15, 2026 [Member]	Dec. 31, 2012 6.375% Senior notes due March 15, 2033 [Member]	Dec. 31, 2011 6.375% Senior notes due March 15, 2033 [Member]	Dec. 31, 2012 Indemnifications related to the sale of business entities [Member]	Dec. 31, 2012 Indemnifications related to the sale of business entities [Member] Travelers [Member]	Dec. 31, 2012 Guarantees on payment of principal, premiums and interest on certain debt obligations [Member] Travelers [Member] 5.00% Senior notes due March 15, 2013 [Member]	Dec. 31, 2012 Guarantees on payment of principal, premiums and interest on certain debt obligations [Member] Travelers [Member] 7.75% Senior notes due April 15, 2026 [Member]	Dec. 31, 2012 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
Maximum amount of contingent obligation								$ 471	$ 95
Amount recognized on balance sheet for contingent obligation								9	9
Period range for term of indemnification provisions arising from sales of business entities, minimum (in years)								7 years	8 years
Amount of certain debt obligations of TPC that are unconditionally guaranteed by the Travelers Companies, Inc.	$ 1,200	$ 500		$ 200		$ 500				$ 500	$ 200	$ 500
Interest rate (percent)		5.00%	5.00%	7.75%	7.75%	6.375%	6.375%			5.00%	7.75%	6.375%