Consolidating Financial Statements (details) - Consolidating Statement of Comprehensive Income (Unaudited) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Consolidating Financial Statements, Captions
Net income	$ 864	$ 333	$ 2,169	$ 808
Change in net unrealized gains on investment securities having no credit losses recognized in the consolidated statement of income	470	687	609	1,226
Change in net unrealized gains on investment securities having credit losses recognized in the consolidated statement of income	41	(9)	71	9
Net changes in benefit plan assets and obligations	22	20	64	57
Net changes in unrealized foreign currency translation and other changes	65	(180)	43	(94)
Other comprehensive income before income taxes	598	518	787	1,198
Income tax expense, other comprehensive income	192	197	256	421
Other comprehensive income, net of taxes	406	321	531	777
Comprehensive income	1,270	654	2,700	1,585
TPC [Member]
Consolidating Financial Statements, Captions
Net income	598	254	1,610	710
Change in net unrealized gains on investment securities having no credit losses recognized in the consolidated statement of income	338	500	451	871
Change in net unrealized gains on investment securities having credit losses recognized in the consolidated statement of income	28	(9)	49	(7)
Net changes in benefit plan assets and obligations	1		1
Net changes in unrealized foreign currency translation and other changes	13	(110)	(20)	(75)
Other comprehensive income before income taxes	380	381	481	789
Income tax expense, other comprehensive income	129	140	165	280
Other comprehensive income, net of taxes	251	241	316	509
Comprehensive income	849	495	1,926	1,219
Other Subsidiaries [Member]
Consolidating Financial Statements, Captions
Net income	310	130	704	173
Change in net unrealized gains on investment securities having no credit losses recognized in the consolidated statement of income	127	198	147	363
Change in net unrealized gains on investment securities having credit losses recognized in the consolidated statement of income	13		22	16
Net changes in benefit plan assets and obligations		1		1
Net changes in unrealized foreign currency translation and other changes	52	(70)	63	(19)
Other comprehensive income before income taxes	192	129	232	361
Income tax expense, other comprehensive income	54	54	65	124
Other comprehensive income, net of taxes	138	75	167	237
Comprehensive income	448	205	871	410
Travelers [Member]
Consolidating Financial Statements, Captions
Net income	864	333	2,169	808
Change in net unrealized gains on investment securities having no credit losses recognized in the consolidated statement of income	470	687	609	1,226
Change in net unrealized gains on investment securities having credit losses recognized in the consolidated statement of income	41	(9)	71	9
Net changes in benefit plan assets and obligations	22	20	64	57
Net changes in unrealized foreign currency translation and other changes	65	(180)	43	(94)
Other comprehensive income before income taxes	598	518	787	1,198
Income tax expense, other comprehensive income	192	197	256	421
Other comprehensive income, net of taxes	406	321	531	777
Comprehensive income	1,270	654	2,700	1,585
Eliminations [Member]
Consolidating Financial Statements, Captions
Net income	(908)	(384)	(2,314)	(883)
Change in net unrealized gains on investment securities having no credit losses recognized in the consolidated statement of income	(465)	(698)	(598)	(1,234)
Change in net unrealized gains on investment securities having credit losses recognized in the consolidated statement of income	(41)	9	(71)	(9)
Net changes in benefit plan assets and obligations	(1)	(1)	(1)	(1)
Net changes in unrealized foreign currency translation and other changes	(65)	180	(43)	94
Other comprehensive income before income taxes	(572)	(510)	(713)	(1,150)
Income tax expense, other comprehensive income	(183)	(194)	(230)	(404)
Other comprehensive income, net of taxes	(389)	(316)	(483)	(746)
Comprehensive income	$ (1,297)	$ (700)	$ (2,797)	$ (1,629)