Consolidating Financial Statements (details) - Consolidating Statement of Comprehensive Income (Unaudited) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Consolidating Statement of Comprehensive Income
Net income (loss)	$ 499	$ (364)	$ 1,305	$ 475
Change in net unrealized gains on investment securities having no credit losses recognized in the consolidated statement of income	216	645	139	539
Change in net unrealized gains on investment securities having credit losses recognized in the consolidated statement of income	5	(10)	30	18
Net changes in benefit plan assets and obligations	22	19	42	37
Net changes in unrealized foreign currency translation and other changes	(86)	16	(22)	86
Other comprehensive income before income taxes	157	670	189	680
Income tax expense, other comprehensive income	66	231	64	224
Other comprehensive income, net of taxes	91	439	125	456
Comprehensive income	590	75	1,430	931
TPC [Member]
Consolidating Statement of Comprehensive Income
Net income (loss)	394	(144)	1,012	456
Change in net unrealized gains on investment securities having no credit losses recognized in the consolidated statement of income	167	441	113	371
Change in net unrealized gains on investment securities having credit losses recognized in the consolidated statement of income	5	(8)	21	2
Net changes in unrealized foreign currency translation and other changes	(54)	13	(33)	35
Other comprehensive income before income taxes	118	446	101	408
Income tax expense, other comprehensive income	43	154	36	140
Other comprehensive income, net of taxes	75	292	65	268
Comprehensive income	469	148	1,077	724
Other Subsidiaries [Member]
Consolidating Statement of Comprehensive Income
Net income (loss)	145	(146)	394	43
Change in net unrealized gains on investment securities having no credit losses recognized in the consolidated statement of income	52	204	20	165
Change in net unrealized gains on investment securities having credit losses recognized in the consolidated statement of income		(2)	9	16
Net changes in benefit plan assets and obligations	1
Net changes in unrealized foreign currency translation and other changes	(32)	4	11	51
Other comprehensive income before income taxes	21	206	40	232
Income tax expense, other comprehensive income	16	71	11	70
Other comprehensive income, net of taxes	5	135	29	162
Comprehensive income	150	(11)	423	205
Travelers [Member]
Consolidating Statement of Comprehensive Income
Net income (loss)	499	(364)	1,305	475
Change in net unrealized gains on investment securities having no credit losses recognized in the consolidated statement of income	216	645	139	539
Change in net unrealized gains on investment securities having credit losses recognized in the consolidated statement of income	5	(10)	30	18
Net changes in benefit plan assets and obligations	22	19	42	37
Net changes in unrealized foreign currency translation and other changes	(86)	16	(22)	86
Other comprehensive income before income taxes	157	670	189	680
Income tax expense, other comprehensive income	66	231	64	224
Other comprehensive income, net of taxes	91	439	125	456
Comprehensive income	590	75	1,430	931
Eliminations [Member]
Consolidating Statement of Comprehensive Income
Net income (loss)	(539)	290	(1,406)	(499)
Change in net unrealized gains on investment securities having no credit losses recognized in the consolidated statement of income	(219)	(645)	(133)	(536)
Change in net unrealized gains on investment securities having credit losses recognized in the consolidated statement of income	(5)	10	(30)	(18)
Net changes in benefit plan assets and obligations	(1)
Net changes in unrealized foreign currency translation and other changes	86	(17)	22	(86)
Other comprehensive income before income taxes	(139)	(652)	(141)	(640)
Income tax expense, other comprehensive income	(59)	(225)	(47)	(210)
Other comprehensive income, net of taxes	(80)	(427)	(94)	(430)
Comprehensive income	$ (619)	$ (137)	$ (1,500)	$ (929)