Schedule II (Details) - Condensed Statement of Cash Flows - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Condensed Statement of Cash Flows
Net income	$ 2,991	$ 2,842	$ 3,662
Deferred federal income tax expense (benefit)	(163)	(186)	62
Other operating activities	647	45	750
Net cash provided by operating activities	7,711	6,465	7,274
Net sales (purchases) of short-term securities	(1,664)	355	1,671
Net cash used in investing activities	(6,821)	(3,728)	(5,196)
Treasury stock acquired — share repurchase authorizations	(958)	(2,000)	(2,156)
Treasury stock acquired — net employee share-based compensation	(64)	(61)	(44)
Dividends paid to shareholders	(908)	(875)	(869)
Issuance of debt	738	0	739
Issuance of common stock — employee share options	141	267	293
Net cash used in financing activities	(1,051)	(2,669)	(2,037)
Net increase (decrease) in cash	(149)	38	40
Cash at beginning of year	799	761	721
Cash at end of year	650	799	761
Cash received during the year for taxes	(201)	(817)	(707)
Cash paid during the year for interest	370	349	337
Travelers [Member]
Condensed Statement of Cash Flows
Net income	2,991	2,842	3,662
Equity in net income of subsidiaries	(3,114)	(3,080)	(3,867)
Dividends received from consolidated subsidiaries	1,125	2,860	2,149
Capital received from subsidiaries	18	0	0
Deferred federal income tax expense (benefit)	17	14	7
Change in income taxes payable	(2)	(13)	0
Other operating activities	142	7	(69)
Net cash provided by operating activities	1,177	2,630	1,882
Net sales (purchases) of short-term securities	(88)	73	167
Other investments, net	(37)	(35)	(11)
Net cash used in investing activities	(125)	38	156
Treasury stock acquired — share repurchase authorizations	(958)	(2,000)	(2,156)
Treasury stock acquired — net employee share-based compensation	(64)	(61)	(44)
Dividends paid to shareholders	(908)	(875)	(869)
Issuance of debt	738	0	739
Issuance of common stock — employee share options	141	267	293
Net cash used in financing activities	(1,051)	(2,669)	(2,037)
Net increase (decrease) in cash	1	(1)	1
Cash at beginning of year	0	1	0
Cash at end of year	1	0	1
Cash received during the year for taxes	73	100	66
Cash paid during the year for interest	$ 322	$ 301	$ 289