Schedule II Schedule II (STATEMENTS OF OPERATIONS - Parent Company Only) (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Condensed Financial Statements, Captions [Line Items]
Equity in net income of subsidiaries and affiliates	[1]	$ 1,019	$ 617	$ 514
Total revenues		35,994	34,186	32,717
Administrative and other (income) expense		2,979	3,030	2,886
Business Combination, Integration Related Costs		0	23	59
Income tax expense (benefit)		629	795	695
Total expenses		31,832	28,937	28,060
Net income		3,533	4,454	3,962
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest		5,783	7,521	1,242
Chubb limited (Parent Guarantor)
Condensed Financial Statements, Captions [Line Items]
Investment income, including intercompany interest income		155	227	305
Equity in net income of subsidiaries and affiliates		3,457	4,307	3,753
Total revenues		3,612	4,534	4,058
Administrative and other (income) expense		55	65	63
Business Combination, Integration Related Costs		0	1	14
Income tax expense (benefit)		24	14	19
Total expenses		79	80	96
Net income		3,533	4,454	3,962
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest		$ 5,783	$ 7,521	$ 1,242

[1] Equity in net income of partially-owned entities includes $167 million, $74 million, and $43 million attributable to our investments in Huatai (Huatai Group, Huatai P&C, and Huatai Life) for the years ended December 31, 2020, 2019, and 2018, respectively.