Consolidated Statements Of Shareholders' Equity - USD ($) $ in Millions	Total	Common Shares	Treasury Stock, Common	Additional Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive Income	Noncontrolling Interest
Noncontrolling interests							$ 0
Balance – beginning of year, net of tax at Dec. 31, 2021		$ 10,985	$ (7,464)	$ 8,478	$ 47,403	$ (1,074)
CB_Par Value Reduction		0		0
Treasury Stock, Retired, Cost Method, Amount		(639)	4,983		(4,344)
Common Shares repurchased			(3,014)
Net shares issued under employee share-based compensation plans			382	(173)
Stock Issued During Period, Value, Stock Options Exercised				(43)
Share-based compensation expense				283
Noncontrolling Interest, Increase from Business Combination				0
FundingDividendsDeclaredToRetainedEarnings				(1,379)
Net income attributable to Chubb	$ 5,246				5,246
Funding Dividends Declared From Additional Paid In Capital					1,379
Dividends declared on Common Shares					(1,379)
Other Comprehensive Income (Loss), Net of Tax	(9,111)					(9,111)
Balance – end of year, net of tax at Dec. 31, 2022	50,519	10,346	(5,113)	7,166	48,305	(10,185)
Net increase (decrease) due to consolidation, deconsolidation, and other transactions							0
Net income (loss) attributable to noncontrolling interests	0						0
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Noncontrolling Interest							0
Other increase (decrease) in noncontrolling interest							0
Noncontrolling interests							0
Total shareholders’ equity	50,519
CB_Par Value Reduction		(9,759)		9,759
Treasury Stock, Retired, Cost Method, Amount		(346)	2,869		(2,523)
Common Shares repurchased			(2,478)
Net shares issued under employee share-based compensation plans			322	(192)
Stock Issued During Period, Value, Stock Options Exercised				(20)
Share-based compensation expense				322
Noncontrolling Interest, Increase from Business Combination				31
FundingDividendsDeclaredToRetainedEarnings				(1,401)
Net income attributable to Chubb	9,028				9,028
Funding Dividends Declared From Additional Paid In Capital					1,401
Dividends declared on Common Shares					(1,401)
Other Comprehensive Income (Loss), Net of Tax	3,361					3,376
Balance – end of year, net of tax at Dec. 31, 2023	59,507	241	(4,400)	15,665	54,810	(6,809)
Net increase (decrease) due to consolidation, deconsolidation, and other transactions							4,212
Net income (loss) attributable to noncontrolling interests	(13)						(13)
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Noncontrolling Interest							(15)
Other increase (decrease) in noncontrolling interest							0
Noncontrolling interests	4,184						4,184
Total shareholders’ equity	63,691
CB_Par Value Reduction		0		0
Treasury Stock, Retired, Cost Method, Amount		(6)	2,527		(2,521)
Common Shares repurchased			(2,024)
Net shares issued under employee share-based compensation plans			373	(124)
Stock Issued During Period, Value, Stock Options Exercised				(23)
Share-based compensation expense				361
Noncontrolling Interest, Increase from Business Combination				(31)
FundingDividendsDeclaredToRetainedEarnings				(1,455)
Net income attributable to Chubb	9,272				9,272
Funding Dividends Declared From Additional Paid In Capital					1,455
Dividends declared on Common Shares					(1,455)
Other Comprehensive Income (Loss), Net of Tax	(1,982)					(1,835)
Balance – end of year, net of tax at Dec. 31, 2024	64,021	$ 235	$ (3,524)	$ 14,393	$ 61,561	$ (8,644)
Net increase (decrease) due to consolidation, deconsolidation, and other transactions							(26)
Net income (loss) attributable to noncontrolling interests	368						368
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Noncontrolling Interest							(147)
Other increase (decrease) in noncontrolling interest							(6)
Noncontrolling interests	4,373						$ 4,373
Total shareholders’ equity	$ 68,394