General (Policies)	3 Months Ended
General (Policies)	Mar. 31, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of presentation	a) Basis of presentation Chubb Limited is a holding company incorporated in Zurich, Switzerland. Chubb Limited, through its subsidiaries, provides a broad range of insurance and reinsurance products to insureds worldwide. Chubb operates through the following business segments: North America Commercial P&C Insurance, North America Personal P&C Insurance, North America Agricultural Insurance, Overseas General Insurance, Global Reinsurance, and Life Insurance. Refer to Note 10 for additional information. The interim unaudited consolidated financial statements, which include the accounts of Chubb Limited and its subsidiaries (collectively, Chubb, we, us, or our), have been prepared in accordance with accounting principles generally accepted in the United States of America (GAAP) and, in the opinion of management, reflect all adjustments (consisting of normally recurring accruals) necessary for a fair statement of the results and financial position for such periods. All significant intercompany accounts and transactions, including internal reinsurance transactions, have been eliminated. The results of operations and cash flows for any interim period are not necessarily indicative of the results for the full year. These consolidated financial statements should be read in conjunction with the consolidated financial statements and related notes included in our 2016 Form 10-K.
Accounting guidance adopted in 2017	d) Accounting guidance adopted in 2017 Stock Compensation Effective January 2017, we prospectively adopted new guidance on stock compensation which requires recognition of the excess tax benefits or deficiencies of share-based compensation awards to employees through net income rather than through additional paid in capital. The calculation of the excess tax benefits or deficiencies is based on the difference between the market value of a stock award at the date of vesting, or at the time of exercise for a stock option, compared to the grant date fair value recognized as compensation expense in the Consolidated statements of operations. For the three months ended March 31, 2017, the excess tax benefit recorded to Income tax expense on the Consolidated statement of operations was $25 million. Additionally, the guidance allows for an election to account for forfeitures related to share-based payments either as they occur or through an estimation method. We elected to retain our current accounting for compensation expense using a forfeiture estimation process.
Accounting guidance not yet adopted	e) Accounting guidance not yet adopted Revenue from Contracts with Customers In May 2014, the Financial Accounting Standards Board (FASB) issued an accounting standard that supersedes most existing revenue recognition guidance. The standard excludes from its scope the accounting for insurance contracts, leases, financial instruments, and certain other agreements that are governed under other GAAP guidance, but could affect the revenue recognition for certain of our claims management and risk control services. The updated guidance requires an entity to recognize revenue as performance obligations are met, in order to reflect the transfer of promised goods or services to customers in an amount that reflects the consideration the entity is entitled to receive for those goods or services. The standard is effective for us in the first quarter of 2018 with early adoption permitted. The adoption of this guidance is not expected to have a material impact on our financial condition or results of operations given that the majority of our business is outside the scope of this guidance. Financial Instruments – Recognition and Measurement of Financial Assets and Financial Liabilities In January 2016, the FASB issued guidance that affects the recognition, measurement, presentation, and disclosure of financial instruments. The guidance requires equity investments to be measured at fair value with changes in fair value recognized through net income (other than those accounted for under equity method of accounting or those that result in consolidation of the investee) and an assessment of a valuation allowance on deferred tax assets related to unrealized losses of available for sale (AFS) debt securities in combination with other deferred tax assets. The standard will be effective for us in the first quarter of 2018. We are in the process of evaluating the effect the updated guidance will have on our financial condition and results of operations. Financial Instruments – Credit Losses: Measurement of Credit Losses on Financial Instruments In June 2016, the FASB issued guidance on the accounting for credit losses of financial instruments that are measured at amortized cost, including held to maturity securities and reinsurance recoverables, by applying an approach based on the current expected credit losses (CECL). The estimate of expected credit losses should consider historical information, current information, as well as reasonable and supportable forecasts, including estimates of prepayments. The allowance for credit losses is a valuation account that is deducted from the amortized cost basis of the financial asset in order to present the net carrying value at the amount expected to be collected on the financial asset on the Consolidated balance sheet. The guidance also amends the current debt security other-than-temporary impairment model by requiring an estimate of the expected credit loss (ECL) only when the fair value is below the amortized cost of the asset. The length of time the fair value of an AFS debt security has been below the amortized cost will no longer impact the determination of whether a potential credit loss exists. The AFS debt security model will also require the use of a valuation allowance as compared to the current practice of writing down the asset. The standard will be effective for us in the first quarter of 2020 with early adoption permitted in the first quarter of 2019. We will be able to assess the effect of adopting this guidance on our financial condition and results of operations closer to the date of adoption. Statement of Cash Flows In August 2016, the FASB issued guidance clarifying the classification of certain cash receipts and cash payments within the statement of cash flows, including distributions received from equity method investments. The guidance requires entities to make an accounting policy election to present cash flows received either in operating cash flows or investing cash flows based on cumulative equity-method earnings or on the nature of the distributions. The updated guidance will be effective for us in the first quarter of 2018 with early adoption permitted. The updated guidance should be applied retrospectively, unless it is impracticable to do so, at which point the guidance should be applied prospectively. We are in the process of evaluating the effect the updated guidance will have on our statements of cash flows. Goodwill Impairment In January 2017, the FASB issued updated guidance on goodwill impairment testing that eliminates Step 2 of the goodwill impairment test requiring entities to calculate the implied fair value of goodwill through a hypothetical purchase price allocation. Under the updated guidance, impairment will now be recognized as the amount by which a reporting unit’s carrying value exceeds its fair value. The standard will be effective for us in the first quarter of 2020 on a prospective basis with early adoption permitted. We do not expect the adoption of this guidance to have a material effect on our financial condition and results of operations.