Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2017	Feb. 09, 2018	Jun. 30, 2017
Document and Entity Information
Registrant name	Travelers Companies, Inc.
Central index key	0000086312
Document type	10-K
Document period end date	Dec. 31, 2017
Amendment flag	false
Current fiscal year end date	--12-31
Well-known seasoned issuer	Yes
Voluntary filers	No
Current reporting status	Yes
Filer category	Large Accelerated Filer
Entity public float			$ 34,813,427,330
Common stock shares outstanding		271,427,959
Document fiscal year focus	2017
Document fiscal period focus	FY