Schedule II (details) - Condensed Statement of Comprehensive Income (USD $) In Millions, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Condensed financial statements
Consolidated net income	$ 304	$ 864	$ 499	$ 806	$ 618	$ 333	$ (364)	$ 839	$ 2,473	$ 1,426	$ 3,216
Changes in net unrealized gains on investment securities having no credit losses recognized in the consolidated statement of income									281	1,570	(118)
Changes in net unrealized gains on investment securities having credit losses recognized in the consolidated statement of income									81	4	123
Net changes in benefit plan assets and obligations									(69)	(307)	39
Net changes in unrealized foreign currency translation and other changes									43	(90)	12
Other comprehensive income before income taxes									336	1,177	56
Income tax expense (benefit)									105	427	20
Other comprehensive income (loss), net of taxes, before other comprehensive income of subsidiaries									231	750	36
Other comprehensive income, net of taxes									231	750	36
Comprehensive income									2,704	2,176	3,252
Travelers [Member]
Condensed financial statements
Consolidated net income									2,473	1,426	3,216
Changes in net unrealized gains on investment securities having no credit losses recognized in the consolidated statement of income									10	(2)	1
Net changes in benefit plan assets and obligations									(58)	(303)	33
Other comprehensive income before income taxes									(48)	(305)	34
Income tax expense (benefit)									(17)	(106)	11
Other comprehensive income (loss), net of taxes, before other comprehensive income of subsidiaries									(31)	(199)	23
Other comprehensive income of subsidiaries									262	949	13
Other comprehensive income, net of taxes									231	750	36
Comprehensive income									$ 2,704	$ 2,176	$ 3,252