Schedule II (BALANCE SHEETS - Parent Company Only) (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Assets
Other assets	$ 7,503	$ 7,508
Total assets	246,548	230,682
Liabilities
Accounts Payable and Accrued Liabilities	10,192	8,332
Total liabilities	178,154	166,991
Stockholders' Equity Attributable to Parent [Abstract]
Common Shares	235	241
Common shares in treasury	(3,524)	(4,400)
Additional paid-in capital	14,393	15,665
Retained earnings	61,561	54,810
Accumulated other comprehensive income (loss)	(8,644)	(6,809)
Total Chubb shareholders' equity	64,021	59,507	$ 50,519
Total liabilities and shareholders’ equity	246,548	230,682
Parent Company Only
Assets
Investments in subsidiaries and affiliates on equity basis	64,141	59,952
Total investments	64,141	59,952
Cash	383	77	$ 40	$ 1
Due from subsidiaries and affiliates, net	629	717
Other assets	13	12
Total assets	65,166	60,758
Liabilities
Affiliated notional cash pooling program	277	594
Accounts Payable and Accrued Liabilities	868	657
Total liabilities	1,145	1,251
Stockholders' Equity Attributable to Parent [Abstract]
Common Shares	235	241
Common shares in treasury	(3,524)	(4,400)
Additional paid-in capital	14,393	15,665
Retained earnings	61,561	54,810
Accumulated other comprehensive income (loss)	(8,644)	(6,809)
Total Chubb shareholders' equity	64,021	59,507
Total liabilities and shareholders’ equity	$ 65,166	$ 60,758