Shareholders' equity note (Tables)

12 Months Ended

Dec. 31, 2020

Stockholders' Equity Note [Abstract]

Dividends Declared [Table Text Block]

The following table presents dividend distributions per Common Share in Swiss francs (CHF) and U.S. dollars (USD):

	Year Ended December 31
		2020			2019			2018
	CHF	USD		CHF	USD		CHF	USD
Total dividend distributions per common share	2.89	$	3.09	2.94	$	2.98	2.84	$	2.90

Schedule of changes in Common Shares issued and outstanding

	Year Ended December 31
	2020	2019	2018
Common Shares authorized and issued, beginning of year	479,783,864	479,783,864	479,783,864
Cancellation of treasury shares	(2,178,600)	—	—
Common Shares authorized and issued, end of year	477,605,264	479,783,864	479,783,864
Common Shares in treasury, beginning of year (at cost)	(27,812,297)	(20,580,486)	(15,950,685)
Net shares issued under employee share-based compensation plans	2,345,208	3,210,427	3,089,234
Shares repurchased	(3,584,150)	(10,442,238)	(7,719,035)
Cancellation of treasury shares	2,178,600	—	—
Common Shares in treasury, end of year (at cost)	(26,872,639)	(27,812,297)	(20,580,486)
Common Shares outstanding, end of year	450,732,625	451,971,567	459,203,378

Share Repurchase Program [Table Text Block]

The following table presents repurchases of Chubb's Common Shares conducted in a series of open market transactions under the Board authorizations:

	Year Ended December 31						January 1, 2021 through
(in millions of U.S. dollars, except share data)	2020		2019		2018		February 24, 2021
Number of shares repurchased	3,584,150		10,442,238		7,719,035		1,971,000
Cost of shares repurchased (1)	$	516	$	1,531	$	1,021	$	327