Shareholders' Equity and Dividend Availability (Details) - Dividend Availability - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Statutory accounting principles
Cash dividends paid	$ 951	$ 908	$ 875
Insurance subsidiaries [Member]
Statutory accounting principles
Statutory net income of the Company's domestic and international insurance subsidiaries	4,740	2,850	2,620
Statutory capital and surplus of the Company's domestic and international insurance subsidiaries	27,720	25,110
Insurance subsidiaries [Member] | United States [Member]
Statutory accounting principles
Cash dividends paid	2,000	1,170	2,900
Travelers [Member]
Statutory accounting principles
Cash dividends paid	$ 951	$ 908	$ 875
Cash dividends declared per common share (in dollars per share)	$ 4.15	$ 3.93	$ 3.67
Connecticut Insurance Department [Member] | Insurance subsidiaries [Member]
Statutory accounting principles
Maximum amount of dividends available to be paid by subsidiaries to their parent without prior approval of the Connecticut Insurance Department	$ 4,170