Consolidated Statements Of Shareholders' Equity (Unaudited) - USD ($) $ in Millions	Total	Common Stock [Member]	Treasury Stock, Common	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Noncontrolling Interest
Noncontrolling interests							$ 0
Balance – beginning of period, net of tax at Dec. 31, 2022		$ 10,346	$ (5,113)	$ 7,166	$ 48,305	$ (10,185)
Par value reduction		(9,759)		(9,759)
Treasury Stock, Retired, Cost Method, Amount		(346)	(2,869)		(2,523)
Common Shares repurchased			(1,758)
Net shares issued under employee share-based compensation plans			(255)
Stock Issued During Period, Value, Restricted Stock Award, Net of Forfeitures				(203)
Exercise of stock options				(15)
Share-based compensation expense				230
Adjustments to Additional Paid in Capital, Other				0
Funding of dividends declared to Retained earnings				(1,050)
Net income attributable to Chubb	$ 5,728				5,728
Funding of dividends declared from Additional paid-in capital					1,050
Dividends declared on Common Shares					(1,050)
Other Comprehensive Income (Loss), Net of Tax	(1,409)					(1,333)
Balance – end of period, net of tax at Sep. 30, 2023	52,373	241	(3,747)	15,887	51,510	(11,518)
Noncontrolling Interest, Decrease from Redemptions or Purchase of Interests							5,210
Net income (loss) attributable to noncontrolling interests	(3)						(3)
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Noncontrolling Interest							(76)
Other							0
Noncontrolling interests							0
Balance – beginning of period, net of tax at Jun. 30, 2023		241	(3,174)	16,163	49,467	(9,822)
Par value reduction		0		0
Treasury Stock, Retired, Cost Method, Amount		0	0		0
Common Shares repurchased			(606)
Net shares issued under employee share-based compensation plans			(33)
Stock Issued During Period, Value, Restricted Stock Award, Net of Forfeitures				3
Exercise of stock options				(2)
Share-based compensation expense				75
Adjustments to Additional Paid in Capital, Other				0
Funding of dividends declared to Retained earnings				(352)
Net income attributable to Chubb	2,043				2,043
Funding of dividends declared from Additional paid-in capital					352
Dividends declared on Common Shares					(352)
Other Comprehensive Income (Loss), Net of Tax	(1,772)					(1,696)
Balance – end of period, net of tax at Sep. 30, 2023	52,373	241	(3,747)	15,887	51,510	(11,518)
Noncontrolling Interest, Decrease from Redemptions or Purchase of Interests							5,210
Net income (loss) attributable to noncontrolling interests	(3)						(3)
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Noncontrolling Interest							(76)
Other							0
Noncontrolling interests							5,131
Total shareholders' equity	57,504
Noncontrolling interests	4,184						4,184
Total shareholders' equity	63,691
Balance – beginning of period, net of tax at Dec. 31, 2023	59,507	241	(4,400)	15,665	54,810	(6,809)
Par value reduction		0		0
Treasury Stock, Retired, Cost Method, Amount		(6)	(2,527)		(2,521)
Common Shares repurchased			(1,299)
Net shares issued under employee share-based compensation plans			(335)
Stock Issued During Period, Value, Restricted Stock Award, Net of Forfeitures				(139)
Exercise of stock options				(22)
Share-based compensation expense				258
Adjustments to Additional Paid in Capital, Other				(31)
Funding of dividends declared to Retained earnings				(1,088)
Net income attributable to Chubb	6,697				6,697
Funding of dividends declared from Additional paid-in capital					1,088
Dividends declared on Common Shares					(1,088)
Other Comprehensive Income (Loss), Net of Tax	1,489					1,539
Balance – end of period, net of tax at Sep. 30, 2024	65,757	235	(2,837)	14,643	58,986	(5,270)
Noncontrolling Interest, Decrease from Redemptions or Purchase of Interests							(68)
Net income (loss) attributable to noncontrolling interests	303						303
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Noncontrolling Interest							(50)
Other							(6)
Noncontrolling interests							3,537
Balance – beginning of period, net of tax at Jun. 30, 2024		235	(2,481)	14,926	56,662	(8,304)
Par value reduction		0		0
Treasury Stock, Retired, Cost Method, Amount		0	0		0
Common Shares repurchased			(413)
Net shares issued under employee share-based compensation plans			(57)
Stock Issued During Period, Value, Restricted Stock Award, Net of Forfeitures				3
Exercise of stock options				(3)
Share-based compensation expense				86
Adjustments to Additional Paid in Capital, Other				0
Funding of dividends declared to Retained earnings				(369)
Net income attributable to Chubb	2,324				2,324
Funding of dividends declared from Additional paid-in capital					369
Dividends declared on Common Shares					(369)
Other Comprehensive Income (Loss), Net of Tax	3,055					3,034
Balance – end of period, net of tax at Sep. 30, 2024	65,757	$ 235	$ (2,837)	$ 14,643	$ 58,986	$ (5,270)
Noncontrolling Interest, Decrease from Redemptions or Purchase of Interests							639
Net income (loss) attributable to noncontrolling interests	166						166
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Noncontrolling Interest							21
Other							0
Noncontrolling interests	4,363						$ 4,363
Total shareholders' equity	$ 70,120