Schedule II (Details) - Condensed Income Statement - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Condensed Statement of Income
Net investment income									$ 2,227	$ 2,468	$ 2,474
Net realized investment gains (losses)									2	113	114
Total revenues	$ 8,397	$ 8,275	$ 7,401	$ 7,908	$ 8,063	$ 8,013	$ 7,834	$ 7,671	31,981	31,581	30,282
Interest expense									339	344	352
Other									4,509	4,365	4,297
Total claims and expenses	6,781	7,289	7,486	7,188	6,989	7,581	7,169	6,704	28,744	28,443	27,321
Income before income taxes	1,616	986	(85)	720	1,074	432	665	967	3,237	3,138	2,961
Income tax expense (benefit)	306	159	(45)	120	201	36	108	171	540	516	438
Net income	$ 1,310	$ 827	$ (40)	$ 600	$ 873	$ 396	$ 557	$ 796	2,697	2,622	2,523
Travelers [Member]
Condensed Statement of Income
Net investment income									19	41	32
Net realized investment gains (losses)									27	33	(13)
Total revenues									46	74	19
Interest expense									292	297	304
Other									18	21	20
Total claims and expenses									310	318	324
Income before income taxes									(264)	(244)	(305)
Income tax expense (benefit)									(61)	(77)	(114)
Loss before net income of subsidiaries									(203)	(167)	(191)
Net income of subsidiaries									2,900	2,789	2,714
Net income									$ 2,697	$ 2,622	$ 2,523