Schedule II Schedule II (STATEMENTS OF OPERATIONS - Parent Company Only) (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Condensed Financial Statements, Captions [Line Items]
Equity in net income of subsidiaries and affiliates									$ 264	$ 113	$ 231
Net realized gains (losses)	$ 365	$ 100	$ (216)	$ (394)	$ (60)	$ (397)	$ 126	$ (89)	(145)	(420)	(507)
Total revenues	8,168	8,527	7,897	6,877	4,679	4,871	5,048	4,389	31,469	18,987	19,171
Administrative and other (income) expense									3,081	2,270	2,245
Income tax expense (benefit)									815	462	634
Total expenses									26,519	15,691	15,684
Net income	$ 1,610	$ 1,360	$ 726	$ 439	$ 683	$ 528	$ 942	$ 681	4,135	2,834	2,853
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest									4,556	908	2,892
Chubb limited (Parent Guarantor)
Condensed Financial Statements, Captions [Line Items]
Investment income, including intercompany interest income									356	35	37
Equity in net income of subsidiaries and affiliates									3,901	2,673	2,707
Net realized gains (losses)									0	0	0
Total revenues									4,257	2,708	2,744
Administrative and other (income) expense									101	(142)	(123)
Income tax expense (benefit)									21	16	14
Total expenses									122	(126)	(109)
Net income									4,135	2,834	2,853
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest									$ 4,556	$ 908	$ 2,892