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v3.19.3.a.u2

Unpaid losses and loss expenses Unpaid losses and loss expenses (Reconciliation of reserve Balances to Liability for Unpaid Loss)(Details) (Details) - USD ($) $ in Millions | Dec. 31, 2019 | Dec. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2016
--- | --- | --- | --- | ---
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items] |  |  |  |  |
Unpaid Loss and Allocated Loss Adjustment Expenses, Net |  | $ 46,062 |  |  |
Reinsurance Recoverable for Unpaid Claims and Claims Adjustments |  | 14,331 |  |  |
Short-duration Insurance Contracts, Liability for Unpaid Claims and Claim Adjustment Expense, Aggregate Reconciling Items | [1] | 873 |  |  |
Unpaid unallocated loss adjustment expenses |  | 1,424 |  |  |
Unpaid losses and loss expenses |  | 62,690 | $ 62,960 | $ 63,179 | $ 60,540
North America Commercial P&C Insurance - Workers' Compensation [Member] |  |  |  |  |
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items] |  |  |  |  |
Unpaid Loss and Allocated Loss Adjustment Expenses, Net |  | 9,414 |  |  |
Reinsurance Recoverable for Unpaid Claims and Claims Adjustments |  | 1,657 |  |  |
North America Commercial P&C Insurance - Liability [Member] |  |  |  |  |
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items] |  |  |  |  |
Unpaid Loss and Allocated Loss Adjustment Expenses, Net |  | 16,447 |  |  |
Reinsurance Recoverable for Unpaid Claims and Claims Adjustments |  | 5,400 |  |  |
North America Commercial P&C Insurance - Other Casualty [Member] |  |  |  |  |
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items] |  |  |  |  |
Unpaid Loss and Allocated Loss Adjustment Expenses, Net |  | 1,913 |  |  |
Reinsurance Recoverable for Unpaid Claims and Claims Adjustments |  | 546 |  |  |
North America Commercial P&C Insurance - Non-Casualty [Member] |  |  |  |  |
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items] |  |  |  |  |
Unpaid Loss and Allocated Loss Adjustment Expenses, Net |  | 1,759 |  |  |
Reinsurance Recoverable for Unpaid Claims and Claims Adjustments |  | 1,150 |  |  |
North America Personal P&C Insurance [Member] |  |  |  |  |
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items] |  |  |  |  |
Unpaid Loss and Allocated Loss Adjustment Expenses, Net |  | 2,525 |  |  |
Reinsurance Recoverable for Unpaid Claims and Claims Adjustments |  | 603 |  |  |
Overseas General Insurance - Casualty [Member] |  |  |  |  |
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items] |  |  |  |  |
Unpaid Loss and Allocated Loss Adjustment Expenses, Net |  | 5,977 |  |  |
Reinsurance Recoverable for Unpaid Claims and Claims Adjustments |  | 2,113 |  |  |
Overseas General Insurance - Non-Casualty [Member] |  |  |  |  |
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items] |  |  |  |  |
Unpaid Loss and Allocated Loss Adjustment Expenses, Net |  | 2,377 |  |  |
Reinsurance Recoverable for Unpaid Claims and Claims Adjustments |  | 1,263 |  |  |
Global Reinsurance - Casualty [Member] |  |  |  |  |
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items] |  |  |  |  |
Unpaid Loss and Allocated Loss Adjustment Expenses, Net |  | 1,177 |  |  |
Reinsurance Recoverable for Unpaid Claims and Claims Adjustments |  | 35 |  |  |
Global Reinsurance - Non-Casualty [Member] |  |  |  |  |
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items] |  |  |  |  |
Unpaid Loss and Allocated Loss Adjustment Expenses, Net |  | 255 |  |  |
Reinsurance Recoverable for Unpaid Claims and Claims Adjustments |  | 107 |  |  |
Short-Duration Insurance, Other [Member] |  |  |  |  |
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items] |  |  |  |  |
Unpaid Loss and Allocated Loss Adjustment Expenses, Net |  | 4,218 |  |  |
Reinsurance Recoverable for Unpaid Claims and Claims Adjustments |  | $ 1,457 |  |  |
[1] | Primarily includes the claims reserve of our International A&H business and Life Insurance segment reserves.

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