Acquisitions (Pro forma) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Business Acquisition [Line Items]
Net premiums earned	$ 13,373	$ 12,674	$ 37,248	$ 33,815
Huatai Group | Pro Forma
Business Acquisition [Line Items]
Net premiums earned		12,674		34,605
Total revenues		13,755		37,589
Net income		1,905		5,595
Net income attributable to Chubb		$ 1,912		$ 5,587