Schedule II (Details) - Condensed Statement of Comprehensive Income - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Condensed Statement of Comprehensive Income
Net income	$ 2,991	$ 2,842	$ 3,662
Changes in net unrealized gains (losses) on investment securities having no credit losses recognized in the consolidated statement of income	2,249	(9,276)	(2,115)
Net changes in benefit plan assets and obligations	106	(87)	455
Other comprehensive income (loss) before income taxes	2,494	(9,640)	(1,671)
Income tax expense (benefit)	520	(2,002)	(362)
Other comprehensive income (loss), net of taxes	1,974	(7,638)	(1,309)
Comprehensive income (loss)	4,965	(4,796)	2,353
Travelers [Member]
Condensed Statement of Comprehensive Income
Net income	2,991	2,842	3,662
Changes in net unrealized gains (losses) on investment securities having no credit losses recognized in the consolidated statement of income	3	(12)	(4)
Net changes in benefit plan assets and obligations	111	(105)	444
Other comprehensive income (loss) before income taxes	114	(117)	440
Income tax expense (benefit)	30	(38)	87
Other comprehensive income (loss), net of taxes, before other comprehensive income (loss) of subsidiaries	84	(79)	353
Other comprehensive income (loss) of subsidiaries	1,890	(7,559)	(1,662)
Other comprehensive income (loss), net of taxes	1,974	(7,638)	(1,309)
Comprehensive income (loss)	$ 4,965	$ (4,796)	$ 2,353