Schedule II (details) - Condensed Statement of Cash Flows - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Condensed Statement of Cash Flows
Net income	$ 866	$ 928	$ 812	$ 833	$ 1,038	$ 919	$ 683	$ 1,052	$ 3,439	$ 3,692	$ 3,673
Deferred federal income tax expense (benefit)									117	121	167
Other operating activities									56	63	262
Net cash provided by operating activities									3,434	3,693	3,816
Net sales (purchases) of short-term securities									(326)	(498)	111
Net cash provided by (used in) investing activities									317	206	(910)
Treasury stock acquired - share repurchase authorization									(3,150)	(3,275)	(2,400)
Treasury stock acquired - net employee share-based compensation									(74)	(57)	(61)
Dividends paid to shareholders									(739)	(729)	(729)
Payment of debt									(400)		(500)
Issuance of debt									392		494
Issuance of common stock - employee share options									183	195	206
Net cash used in financing activities									(3,733)	(3,809)	(2,939)
Net increase (decrease) in cash									6	80	(36)
Cash at beginning of year				374				294	374	294	330
Cash at end of year	380				374				380	374	294
Cash received during the year for taxes									(1,207)	(1,147)	(1,057)
Cash paid during the year for interest									365	365	355
Travelers [Member]
Condensed Statement of Cash Flows
Net income									3,439	3,692	3,673
Equity in net income of subsidiaries									(3,664)	(3,904)	(3,815)
Dividends received from consolidated subsidiaries									3,833	4,071	2,423
Capital received from (contributed to) subsidiaries									3		(500)
Deferred federal income tax expense (benefit)									(6)	51	(59)
Change in income taxes payable									51	(87)	48
Other operating activities									113	(13)	238
Net cash provided by operating activities									3,769	3,810	2,008
Net sales (purchases) of short-term securities									(16)	(7)	435
Other investments, net									(20)	5	(3)
Net cash provided by (used in) investing activities									(36)	(2)	432
Treasury stock acquired - share repurchase authorization									(3,150)	(3,275)	(2,400)
Treasury stock acquired - net employee share-based compensation									(74)	(57)	(61)
Dividends paid to shareholders									(739)	(729)	(729)
Payment of debt									(400)
Issuance of debt									392		494
Issuance of common stock - employee share options									183	195	206
Other financing activities									55	57	51
Net cash used in financing activities									(3,733)	(3,809)	(2,439)
Net increase (decrease) in cash										(1)	1
Cash at beginning of year				$ 2				$ 3	2	3	2
Cash at end of year	$ 2				$ 2				2	2	3
Cash received during the year for taxes									209	136	210
Cash paid during the year for interest									$ 318	$ 318	$ 295