Consolidating Financial Statements (details) - Consolidating Statement of Comprehensive Income (Unaudited) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Consolidating Statement of Comprehensive Income
Net income	$ 691	$ 833
Changes in net unrealized gains on investment securities having no credit losses recognized in the consolidated statement of income	714	169
Changes in net unrealized gains on investment securities having credit losses recognized in the consolidated statement of income	5	(5)
Net changes in benefit plan assets and obligations	16	24
Net changes in unrealized foreign currency translation	103	(274)
Other comprehensive income (loss) before income taxes	838	(86)
Income tax expense	267	25
Other comprehensive income (loss), net of taxes, before other comprehensive income (loss) of subsidiaries	571	(111)
Other comprehensive income (loss), net of taxes	571	(111)
Comprehensive income	1,262	722
TPC [Member]
Consolidating Statement of Comprehensive Income
Net income	525	632
Changes in net unrealized gains on investment securities having no credit losses recognized in the consolidated statement of income	485	134
Changes in net unrealized gains on investment securities having credit losses recognized in the consolidated statement of income	2	(4)
Net changes in unrealized foreign currency translation	94	(179)
Other comprehensive income (loss) before income taxes	581	(49)
Income tax expense	181	14
Other comprehensive income (loss), net of taxes, before other comprehensive income (loss) of subsidiaries	400	(63)
Other comprehensive income (loss), net of taxes	400	(63)
Comprehensive income	925	569
Other Subsidiaries [Member]
Consolidating Statement of Comprehensive Income
Net income	205	255
Changes in net unrealized gains on investment securities having no credit losses recognized in the consolidated statement of income	228	33
Changes in net unrealized gains on investment securities having credit losses recognized in the consolidated statement of income	3	(1)
Net changes in benefit plan assets and obligations	1	1
Net changes in unrealized foreign currency translation	9	(95)
Other comprehensive income (loss) before income taxes	241	(62)
Income tax expense	79	3
Other comprehensive income (loss), net of taxes, before other comprehensive income (loss) of subsidiaries	162	(65)
Other comprehensive income (loss), net of taxes	162	(65)
Comprehensive income	367	190
Travelers [Member]
Consolidating Statement of Comprehensive Income
Net income	691	833
Changes in net unrealized gains on investment securities having no credit losses recognized in the consolidated statement of income	1	2
Net changes in benefit plan assets and obligations	15	23
Other comprehensive income (loss) before income taxes	16	25
Income tax expense	7	8
Other comprehensive income (loss), net of taxes, before other comprehensive income (loss) of subsidiaries	9	17
Other comprehensive income (loss) of subsidiaries	562	(128)
Other comprehensive income (loss), net of taxes	571	(111)
Comprehensive income	1,262	722
Eliminations [Member]
Consolidating Statement of Comprehensive Income
Net income	(730)	(887)
Other comprehensive income (loss) of subsidiaries	(562)	128
Other comprehensive income (loss), net of taxes	(562)	128
Comprehensive income	$ (1,292)	$ (759)