Document and Entity Information - USD ($) $ in Billions	12 Months Ended
	Dec. 31, 2017	Feb. 12, 2018	Jun. 30, 2017
Document Documentand Entity Information [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2017
Document Fiscal Year Focus	2017
Document Fiscal Period Focus	FY
Trading Symbol	CB
Entity Registrant Name	Chubb Ltd
Entity Central Index Key	0000896159
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		464,091,254
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Public Float			$ 67