Consolidating Financial Statements (details) - Consolidated Statement of Comprehensive Income (Unaudited) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Consolidating financial statements
Net income	$ 896	$ 806
Changes in net unrealized gains on investment securities having no credit losses recognized in the consolidated statement of income	(376)	(77)
Changes in net unrealized gains on investment securities having credit losses recognized in the consolidated statement of income	9	25
Net changes in benefit plan assets and obligations	28	20
Net changes in unrealized foreign currency translation	(96)	64
Other comprehensive income (loss) before income taxes	(435)	32
Income tax expense (benefit)	(125)	(2)
Other comprehensive income (loss), net of taxes, before other comprehensive income (loss) of subsidiaries	(310)	34
Other comprehensive income (loss), net of taxes	(310)	34
Comprehensive income	586	840
TPC [Member]
Consolidating financial statements
Net income	650	618
Changes in net unrealized gains on investment securities having no credit losses recognized in the consolidated statement of income	(315)	(54)
Changes in net unrealized gains on investment securities having credit losses recognized in the consolidated statement of income	7	16
Net changes in benefit plan assets and obligations	1
Net changes in unrealized foreign currency translation	(10)	21
Other comprehensive income (loss) before income taxes	(317)	(17)
Income tax expense (benefit)	(108)	(7)
Other comprehensive income (loss), net of taxes, before other comprehensive income (loss) of subsidiaries	(209)	(10)
Other comprehensive income (loss), net of taxes	(209)	(10)
Comprehensive income	441	608
Other Subsidiaries [Member]
Consolidating financial statements
Net income	293	249
Changes in net unrealized gains on investment securities having no credit losses recognized in the consolidated statement of income	(67)	(32)
Changes in net unrealized gains on investment securities having credit losses recognized in the consolidated statement of income	2	9
Net changes in benefit plan assets and obligations	2	(1)
Net changes in unrealized foreign currency translation	(86)	43
Other comprehensive income (loss) before income taxes	(149)	19
Income tax expense (benefit)	(28)	(5)
Other comprehensive income (loss), net of taxes, before other comprehensive income (loss) of subsidiaries	(121)	24
Other comprehensive income (loss), net of taxes	(121)	24
Comprehensive income	172	273
Travelers [Member]
Consolidating financial statements
Net income	896	806
Changes in net unrealized gains on investment securities having no credit losses recognized in the consolidated statement of income	6	9
Net changes in benefit plan assets and obligations	25	21
Other comprehensive income (loss) before income taxes	31	30
Income tax expense (benefit)	11	10
Other comprehensive income (loss), net of taxes, before other comprehensive income (loss) of subsidiaries	20	20
Other comprehensive income (loss) of subsidiaries	(330)	14
Other comprehensive income (loss), net of taxes	(310)	34
Comprehensive income	586	840
Eliminations [Member]
Consolidating financial statements
Net income	(943)	(867)
Other comprehensive income (loss) of subsidiaries	330	(14)
Other comprehensive income (loss), net of taxes	330	(14)
Comprehensive income	$ (613)	$ (881)