Restricted Stock Units Issued To Non-management Directors During Period, Shares, Restricted Stock Award

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The number of deferred restricted stock units outstanding at the end of the period.

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Description of the period of time an employee has to exercise their options.

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Aggregate number of common shares reserved for future issuance.

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Amount of cost not yet recognized for nonvested award under share-based payment arrangement.

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Weighted-average period over which cost not yet recognized is expected to be recognized for award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

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This item represents the amount of cash contributions during the period made by the entity to the Employee Stock Ownership Plan (ESOP).

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Amount of cash inflow from exercise of option under share-based payment arrangement.

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Period over which grantee's right to exercise award under share-based payment arrangement is no longer contingent on satisfaction of service or performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Includes, but is not limited to, combination of market, performance or service condition.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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The highest percentage of annual salary that an employee is permitted to utilize with respect to the plan.

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Number of shares authorized for issuance under share-based payment arrangement.

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Weighted average remaining contractual term for vested portions of options outstanding and currently exercisable or convertible, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Weighted average remaining contractual term for option awards outstanding, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Purchase price of common stock expressed as a percentage of its fair value.

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Number of shares issued during the period as a result of an employee stock purchase plan.

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Aggregate change in value for stock issued during the period as a result of employee stock purchase plan.

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Share-based compensation (Narrative) (Detail) - USD ($)	12 Months Ended
Share-based compensation (Narrative) (Detail) - USD ($)	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expense related to the unvested share-based awards	$ 263,000,000
Weighted-average expected recognition period for the unrecognized compensation expense	1 year 6 months
Weighted average remaining contractual term for stock options outstanding	5 years 10 months 24 days
Weighted-average remaining contractual term for stock options exercisable	4 years 8 months 12 days
Cash received from exercise of stock options	$ 253,000,000
Restricted stock awards granted to non-management directors	15,586	27,679	19,019
Amounts paid during period by employees for the purchase of shares under the ESPP	$ 47,000,000	$ 45,000,000	$ 41,000,000
Number of shares purchased during period by employees pursuant to the provisions of the ESPP	315,405	383,751	321,800
Discounted purchase price from market price for the ESPP	85.00%
Share-based Compensation Arrangement by Share-based Payment Award, Maximum Employee Subscription Rate for the ESPP	10.00%
Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Employee Stock Purchase Plan Authorized Amount	$ 25,000
Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period of award	3 years
Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period of award	3 years
Stock option term in years	10 years
Restricted stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period of award	4 years
Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of deferred restricted stock units	139,587
ACE Limited 2004 Long-Term Incentive Plan [Member] \| Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period of award	1 year
Chubb Limited 2016 Long-Term Incentive Plan, amended and restated [Member] \| Restricted stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period of award	4 years
Legacy Chubb Corp \| Restricted Stock Units (RSUs) \| Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period of award	1 year
Legacy Chubb Corp \| Restricted Stock Units (RSUs) \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period of award	3 years
Common shares \| Employee Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common shares authorized for issuance under plan	6,500,000
Common Stock, Capital Shares Reserved for Future Issuance	1,086,822
Common shares \| Chubb Limited 2016 Long-Term Incentive Plan, amended and restated [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common shares authorized for issuance under plan	32,900,000
Common Stock, Capital Shares Reserved for Future Issuance	18,040,720