Schedule II (Details) - Condensed Statement of Comprehensive Income - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Condensed Statement of Comprehensive Income
Net income	$ 4,999	$ 2,991	$ 2,842
Changes in net unrealized gains (losses) on investment securities having no credit losses recognized in the consolidated statement of income	(644)	2,249	(9,276)
Net changes in benefit plan assets and obligations	296	106	(87)
Other comprehensive income (loss) before income taxes	(575)	2,494	(9,640)
Income tax expense (benefit)	(79)	520	(2,002)
Other comprehensive income (loss), net of taxes	(496)	1,974	(7,638)
Comprehensive income (loss)	4,503	4,965	(4,796)
Travelers [Member]
Condensed Statement of Comprehensive Income
Net income	4,999	2,991	2,842
Changes in net unrealized gains (losses) on investment securities having no credit losses recognized in the consolidated statement of income	(1)	3	(12)
Net changes in benefit plan assets and obligations	294	111	(105)
Other comprehensive income (loss) before income taxes	293	114	(117)
Income tax expense (benefit)	61	30	(38)
Other comprehensive income (loss), net of taxes, before other comprehensive income (loss) of subsidiaries	232	84	(79)
Other comprehensive income (loss) of subsidiaries	(728)	1,890	(7,559)
Other comprehensive income (loss), net of taxes	(496)	1,974	(7,638)
Comprehensive income (loss)	$ 4,503	$ 4,965	$ (4,796)