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v3.19.3.a.u2

Unpaid losses and loss expenses (Narrative) (Details) - USD ($) $ in Millions | 12 Months Ended |  |  |  |
--- | --- | --- | --- | --- | ---
Dec. 31, 2019 | Dec. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2011 | Dec. 31, 2010 | Dec. 31, 2004
Liability for Claims and Claims Adjustment Expense [Line Items] |  |  |  |  |  |  |  |
Net Prior Period Development |  | $ (792) | $ (896) | $ (829) |  |  |  |
Prior Period Development, net Adjustments |  | $ 53 | $ 85 | $ 108 |  |  |  |
Prior Period Development Percentage Opening Net Unpaid Reserves | [1] | 1.60% | 1.80% | 1.70% |  |  |  |
Incurred activity |  | $ 18,730 | $ 18,067 | $ 18,454 |  |  |  |
Liability for Claims and Claims Adjustment Expense |  | 62,690 | 62,960 | 63,179 | $ 60,540 |  |  |
Brandywine Run-off [Member] |  |  |  |  |  |  |  |
Liability for Claims and Claims Adjustment Expense [Line Items] |  |  |  |  |  |  |  |
Incurred activity |  | 622 |  |  |  |  |  |
Reinsurance coverage to Century provided by ACE INA under XOL |  | 800 |  |  |  |  |  |
Statutory capital and surplus |  | 25 |  |  |  |  |  |
Dividend retention fund established by INA Financial Corporation |  | 50 |  |  |  |  |  |
Required minimum balance under the dividend retention fund |  | 50 |  |  |  |  |  |
Contributions to the dividend retention fund |  | 90 | 50 |  |  | $ 35 | $ 15 |
Minimum contribution from the dividend retention fund to Century not required for XOL agreement |  | 200 |  |  |  |  |  |
Dividend Retention Fund Contribution to XOL |  | 64 | 39 |  |  |  |  |
Aggregate reinsurance balances ceded by active ACE companies to Century |  | 1,500 | 1,500 |  |  |  |  |
Liability for Claims and Claims Adjustment Expense |  | $ 1,800 | 2,000 |  |  |  |  |
Surplus note |  |  |  |  |  |  |  | $ 100
Westchester and Brandywine Run-off [Member] |  |  |  |  |  |  |  |
Liability for Claims and Claims Adjustment Expense [Line Items] |  |  |  |  |  |  |  |
NICO pro-rata share of reinsurance protection (percent) |  | 75.00% |  |  |  |  |  |
NICO retention for losses and loss expenses incurred on or before 12/31/1996 |  | $ 721 |  |  |  |  |  |
NICO reinsurance protection on losses and loss expenses incurred on or before 12/31/1996, net of retenion |  | 1,000 |  |  |  |  |  |
NICO reinsurance protection on losses and loss expenses |  | 384 |  |  |  |  |  |
Long Tail [Member] |  |  |  |  |  |  |  |
Liability for Claims and Claims Adjustment Expense [Line Items] |  |  |  |  |  |  |  |
Net Prior Period Development |  | (642) | (486) | (423) |  |  |  |
Short Tail [Member] |  |  |  |  |  |  |  |
Liability for Claims and Claims Adjustment Expense [Line Items] |  |  |  |  |  |  |  |
Net Prior Period Development |  | (150) | (410) | (406) |  |  |  |
North America Commercial P&C Insurance |  |  |  |  |  |  |  |
Liability for Claims and Claims Adjustment Expense [Line Items] |  |  |  |  |  |  |  |
Net Prior Period Development |  | (649) | $ (610) | $ (746) |  |  |  |
Prior Period Development, net Adjustments |  | $ 34 |  |  |  |  |  |
Prior Period Development Percentage Opening Net Unpaid Reserves | [1] | 1.30% | 1.20% | 1.60% |  |  |  |
North America Commercial P&C Insurance | Long Tail [Member] |  |  |  |  |  |  |  |
Liability for Claims and Claims Adjustment Expense [Line Items] |  |  |  |  |  |  |  |
Net Prior Period Development |  | $ (668) | $ (395) | $ (562) |  |  |  |
Prior Period Development, net Adjustments |  | 39 |  |  |  |  |  |
North America Commercial P&C Insurance | Short Tail [Member] |  |  |  |  |  |  |  |
Liability for Claims and Claims Adjustment Expense [Line Items] |  |  |  |  |  |  |  |
Net Prior Period Development |  | 19 | (215) | (184) |  |  |  |
Prior Period Development, net Adjustments |  | (5) |  |  |  |  |  |
North America Commercial P&C Insurance | North America Commercial P&C Insurance - Workers' Compensation [Member] | Long Tail [Member] |  |  |  |  |  |  |  |
Liability for Claims and Claims Adjustment Expense [Line Items] |  |  |  |  |  |  |  |
Net Prior Period Development |  | (303) | (194) |  |  |  |  |
North America Commercial P&C Insurance | Commercial Excess and Umbrella [Member] | Long Tail [Member] |  |  |  |  |  |  |  |
Liability for Claims and Claims Adjustment Expense [Line Items] |  |  |  |  |  |  |  |
Net Prior Period Development |  | (41) |  |  |  |  |  |
North America Commercial P&C Insurance | Multi-Line [Member] | Long Tail [Member] |  |  |  |  |  |  |  |
Liability for Claims and Claims Adjustment Expense [Line Items] |  |  |  |  |  |  |  |
Net Prior Period Development |  | (34) |  |  |  |  |  |
North America Commercial P&C Insurance | Credit-related [Member] | Short Tail [Member] |  |  |  |  |  |  |  |
Liability for Claims and Claims Adjustment Expense [Line Items] |  |  |  |  |  |  |  |
Net Prior Period Development |  |  | (19) |  |  |  |  |
North America Commercial P&C Insurance | Other [Member] | Long Tail [Member] |  |  |  |  |  |  |  |
Liability for Claims and Claims Adjustment Expense [Line Items] |  |  |  |  |  |  |  |
Net Prior Period Development |  | 26 |  |  |  |  |  |
North America Commercial P&C Insurance | Other [Member] | Short Tail [Member] |  |  |  |  |  |  |  |
Liability for Claims and Claims Adjustment Expense [Line Items] |  |  |  |  |  |  |  |
Net Prior Period Development |  |  | (60) |  |  |  |  |
North America Commercial P&C Insurance | Commercial Property and Marine [Member] | Short Tail [Member] |  |  |  |  |  |  |  |
Liability for Claims and Claims Adjustment Expense [Line Items] |  |  |  |  |  |  |  |
Net Prior Period Development |  |  | (155) |  |  |  |  |
North America Commercial P&C Insurance | Auto Liability Excess Lines [Member] | Long Tail [Member] |  |  |  |  |  |  |  |
Liability for Claims and Claims Adjustment Expense [Line Items] |  |  |  |  |  |  |  |
Net Prior Period Development |  | 38 |  |  |  |  |  |
North America Commercial P&C Insurance | Non-catastrophe [Member] | Property and Inland Marine [Member] | Short Tail [Member] |  |  |  |  |  |  |  |
Liability for Claims and Claims Adjustment Expense [Line Items] |  |  |  |  |  |  |  |
Net Prior Period Development |  | 108 |  |  |  |  |  |
North America Commercial P&C Insurance | Catastrophe [Member] | Property and Inland Marine [Member] | Short Tail [Member] |  |  |  |  |  |  |  |
Liability for Claims and Claims Adjustment Expense [Line Items] |  |  |  |  |  |  |  |
Net Prior Period Development |  | (36) |  |  |  |  |  |
North America Commercial P&C Insurance | Accident years 2015 through 2017 [Member] | Medical Portfolios [Member] | Long Tail [Member] |  |  |  |  |  |  |  |
Liability for Claims and Claims Adjustment Expense [Line Items] |  |  |  |  |  |  |  |
Net Prior Period Development |  |  | 91 |  |  |  |  |
North America Commercial P&C Insurance | Accident years 2015 through 2017 [Member] | Other [Member] | Long Tail [Member] |  |  |  |  |  |  |  |
Liability for Claims and Claims Adjustment Expense [Line Items] |  |  |  |  |  |  |  |
Net Prior Period Development |  |  | 109 |  |  |  |  |
North America Commercial P&C Insurance | Accident years 2014 and prior [Member] | North America Commercial P&C Insurance - Workers' Compensation [Member] | Long Tail [Member] |  |  |  |  |  |  |  |
Liability for Claims and Claims Adjustment Expense [Line Items] |  |  |  |  |  |  |  |
Net Prior Period Development |  |  | (138) |  |  |  |  |
North America Commercial P&C Insurance | Accident years 2014 and prior [Member] | Foreign Casualty Line [Member] | Long Tail [Member] |  |  |  |  |  |  |  |
Liability for Claims and Claims Adjustment Expense [Line Items] |  |  |  |  |  |  |  |
Net Prior Period Development |  |  | (28) |  |  |  |  |
North America Commercial P&C Insurance | Short-duration Insurance Contracts, Accident Year 2015 [Member] | Political [Member] | Long Tail [Member] |  |  |  |  |  |  |  |
Liability for Claims and Claims Adjustment Expense [Line Items] |  |  |  |  |  |  |  |
Net Prior Period Development |  | (23) |  |  |  |  |  |
North America Commercial P&C Insurance | Accident years 2012 and prior [Member] | Commercial Excess and Umbrella [Member] | Long Tail [Member] |  |  |  |  |  |  |  |
Liability for Claims and Claims Adjustment Expense [Line Items] |  |  |  |  |  |  |  |
Net Prior Period Development |  |  | (100) |  |  |  |  |
North America Commercial P&C Insurance | Accident years 2002 and prior [Member] | Professional Liability [Member] | Long Tail [Member] |  |  |  |  |  |  |  |
Liability for Claims and Claims Adjustment Expense [Line Items] |  |  |  |  |  |  |  |
Net Prior Period Development |  |  | (33) |  |  |  |  |
North America Commercial P&C Insurance | Short-duration Insurance Contracts, Accident Year 2014 [Member] | Political [Member] | Long Tail [Member] |  |  |  |  |  |  |  |
Liability for Claims and Claims Adjustment Expense [Line Items] |  |  |  |  |  |  |  |
Net Prior Period Development |  |  | (23) |  |  |  |  |
North America Commercial P&C Insurance | Accident Year 2013 and prior [Member] | Management Liability [Member] | Long Tail [Member] |  |  |  |  |  |  |  |
Liability for Claims and Claims Adjustment Expense [Line Items] |  |  |  |  |  |  |  |
Net Prior Period Development |  |  | (199) |  |  |  |  |
North America Commercial P&C Insurance | Accident years 2017 - 2018 [Member] | Catastrophe [Member] | Property and Inland Marine [Member] | Short Tail [Member] |  |  |  |  |  |  |  |
Liability for Claims and Claims Adjustment Expense [Line Items] |  |  |  |  |  |  |  |
Net Prior Period Development |  | (41) |  |  |  |  |  |
North America Commercial P&C Insurance | Short-duration Insurance Contracts, Accident Year 2017 [Member] | North America Commercial P&C Insurance - Workers' Compensation [Member] | Long Tail [Member] |  |  |  |  |  |  |  |
Liability for Claims and Claims Adjustment Expense [Line Items] |  |  |  |  |  |  |  |
Net Prior Period Development |  |  | (56) |  |  |  |  |
North America Commercial P&C Insurance | Short-duration Insurance Contracts, Accident Year 2017 [Member] | Credit-related [Member] | Short Tail [Member] |  |  |  |  |  |  |  |
Liability for Claims and Claims Adjustment Expense [Line Items] |  |  |  |  |  |  |  |
Net Prior Period Development |  | (49) |  |  |  |  |  |
North America Commercial P&C Insurance | Short-duration Insurance Contracts, Accident Year 2017 [Member] | Catastrophe [Member] | Commercial Property and Marine [Member] | Short Tail [Member] |  |  |  |  |  |  |  |
Liability for Claims and Claims Adjustment Expense [Line Items] |  |  |  |  |  |  |  |
Net Prior Period Development |  |  | (129) |  |  |  |  |
North America Commercial P&C Insurance | Short-duration Insurance Contracts, Accident Year 2018 [Member] | North America Commercial P&C Insurance - Workers' Compensation [Member] | Long Tail [Member] |  |  |  |  |  |  |  |
Liability for Claims and Claims Adjustment Expense [Line Items] |  |  |  |  |  |  |  |
Net Prior Period Development |  | (61) |  |  |  |  |  |
North America Commercial P&C Insurance | Short-duration Insurance Contracts, Accident Year 2018 [Member] | Property and Inland Marine [Member] | Short Tail [Member] |  |  |  |  |  |  |  |
Liability for Claims and Claims Adjustment Expense [Line Items] |  |  |  |  |  |  |  |
Net Prior Period Development |  | 152 |  |  |  |  |  |
North America Commercial P&C Insurance | Accident years 2017 and prior [Member] | Non-catastrophe [Member] | Property and Inland Marine [Member] | Short Tail [Member] |  |  |  |  |  |  |  |
Liability for Claims and Claims Adjustment Expense [Line Items] |  |  |  |  |  |  |  |
Net Prior Period Development |  | (44) |  |  |  |  |  |
North America Commercial P&C Insurance | Accident Year 2015 and prior [Member] | Professional Errors and Omissions Insurance [Member] | Long Tail [Member] |  |  |  |  |  |  |  |
Liability for Claims and Claims Adjustment Expense [Line Items] |  |  |  |  |  |  |  |
Net Prior Period Development |  | (60) |  |  |  |  |  |
North America Commercial P&C Insurance | Accident Year 2015 and prior [Member] | Foreign Casualty Line [Member] | Long Tail [Member] |  |  |  |  |  |  |  |
Liability for Claims and Claims Adjustment Expense [Line Items] |  |  |  |  |  |  |  |
Net Prior Period Development |  | (39) |  |  |  |  |  |
North America Commercial P&C Insurance | Accident Year 2015 and prior [Member] | Multi-Line [Member] | Long Tail [Member] |  |  |  |  |  |  |  |
Liability for Claims and Claims Adjustment Expense [Line Items] |  |  |  |  |  |  |  |
Net Prior Period Development |  | (36) |  |  |  |  |  |
North America Commercial P&C Insurance | Accident Year 2015 and prior [Member] | Medical and Life Sciences [Member] | Long Tail [Member] |  |  |  |  |  |  |  |
Liability for Claims and Claims Adjustment Expense [Line Items] |  |  |  |  |  |  |  |
Net Prior Period Development |  | (24) |  |  |  |  |  |
North America Commercial P&C Insurance | Accident Year 2015 and prior [Member] | Management Liability [Member] | Long Tail [Member] |  |  |  |  |  |  |  |
Liability for Claims and Claims Adjustment Expense [Line Items] |  |  |  |  |  |  |  |
Net Prior Period Development |  | (217) |  |  |  |  |  |
North America Personal P&C Insurance [Member] |  |  |  |  |  |  |  |
Liability for Claims and Claims Adjustment Expense [Line Items] |  |  |  |  |  |  |  |
Net Prior Period Development |  | $ (95) | $ 41 | $ 69 |  |  |  |
Prior Period Development Percentage Opening Net Unpaid Reserves | [1] | 0.20% | 0.10% | 0.10% |  |  |  |
North America Personal P&C Insurance [Member] | Long Tail [Member] |  |  |  |  |  |  |  |
Liability for Claims and Claims Adjustment Expense [Line Items] |  |  |  |  |  |  |  |
Net Prior Period Development |  | $ 0 | $ 0 | $ 0 |  |  |  |
North America Personal P&C Insurance [Member] | Short Tail [Member] |  |  |  |  |  |  |  |
Liability for Claims and Claims Adjustment Expense [Line Items] |  |  |  |  |  |  |  |
Net Prior Period Development |  | (95) | 41 | 69 |  |  |  |
Prior Period Development, net Adjustments |  | (4) |  |  |  |  |  |
North America Personal P&C Insurance [Member] | Auto Liability and Marine [Member] | Short Tail [Member] |  |  |  |  |  |  |  |
Liability for Claims and Claims Adjustment Expense [Line Items] |  |  |  |  |  |  |  |
Net Prior Period Development |  | (16) |  |  |  |  |  |
North America Personal P&C Insurance [Member] | Short-duration Insurance Contracts, Accident Year 2015 [Member] | Personal Excess [Member] |  |  |  |  |  |  |  |
Liability for Claims and Claims Adjustment Expense [Line Items] |  |  |  |  |  |  |  |
Net Prior Period Development |  |  | (24) |  |  |  |  |
North America Personal P&C Insurance [Member] | Accident years 2017 - 2018 [Member] | Catastrophe [Member] | Short Tail [Member] |  |  |  |  |  |  |  |
Liability for Claims and Claims Adjustment Expense [Line Items] |  |  |  |  |  |  |  |
Net Prior Period Development |  | (132) |  |  |  |  |  |
North America Personal P&C Insurance [Member] | Short-duration Insurance Contracts, Accident Year 2016 [Member] | Personal lines [Member] | Short Tail [Member] |  |  |  |  |  |  |  |
Liability for Claims and Claims Adjustment Expense [Line Items] |  |  |  |  |  |  |  |
Net Prior Period Development |  | (26) |  |  |  |  |  |
North America Personal P&C Insurance [Member] | Short-duration Insurance Contracts, Accident Year 2017 [Member] | Homeowners and Valuables Lines [Member] |  |  |  |  |  |  |  |
Liability for Claims and Claims Adjustment Expense [Line Items] |  |  |  |  |  |  |  |
Net Prior Period Development |  |  | 63 |  |  |  |  |
North America Personal P&C Insurance [Member] | Short-duration Insurance Contracts, Accident Year 2017 [Member] | Catastrophe [Member] | Homeowners and Valuables Lines [Member] |  |  |  |  |  |  |  |
Liability for Claims and Claims Adjustment Expense [Line Items] |  |  |  |  |  |  |  |
Net Prior Period Development |  |  | (73) |  |  |  |  |
North America Personal P&C Insurance [Member] | Short-duration Insurance Contracts, Accident Year 2017 [Member] | Excluding Catastrophic Events [Member] | Homeowners and Valuables Lines [Member] |  |  |  |  |  |  |  |
Liability for Claims and Claims Adjustment Expense [Line Items] |  |  |  |  |  |  |  |
Net Prior Period Development |  |  | 136 |  |  |  |  |
North America Personal P&C Insurance [Member] | Short-duration Insurance Contracts, Accident Year 2018 [Member] | Homeowners and Valuables [Member] | Short Tail [Member] |  |  |  |  |  |  |  |
Liability for Claims and Claims Adjustment Expense [Line Items] |  |  |  |  |  |  |  |
Net Prior Period Development |  | 82 |  |  |  |  |  |
North America Agricultural Insurance |  |  |  |  |  |  |  |
Liability for Claims and Claims Adjustment Expense [Line Items] |  |  |  |  |  |  |  |
Net Prior Period Development |  | $ (80) | $ (110) | $ (119) |  |  |  |
Prior Period Development Percentage Opening Net Unpaid Reserves | [1] | 0.20% | 0.20% | 0.20% |  |  |  |
North America Agricultural Insurance | Long Tail [Member] |  |  |  |  |  |  |  |
Liability for Claims and Claims Adjustment Expense [Line Items] |  |  |  |  |  |  |  |
Net Prior Period Development |  | $ 0 | $ 0 | $ 0 |  |  |  |
North America Agricultural Insurance | Short Tail [Member] |  |  |  |  |  |  |  |
Liability for Claims and Claims Adjustment Expense [Line Items] |  |  |  |  |  |  |  |
Net Prior Period Development |  | (80) | (110) | (119) |  |  |  |
Prior Period Development, net Adjustments |  | 23 |  |  |  |  |  |
Overseas General Insurance |  |  |  |  |  |  |  |
Liability for Claims and Claims Adjustment Expense [Line Items] |  |  |  |  |  |  |  |
Net Prior Period Development |  | (92) | $ (212) | $ (252) |  |  |  |
Prior Period Development, net Adjustments |  | $ 1 |  |  |  |  |  |
Prior Period Development Percentage Opening Net Unpaid Reserves | [1] | 0.20% | 0.40% | 0.50% |  |  |  |
Overseas General Insurance | Long Tail [Member] |  |  |  |  |  |  |  |
Liability for Claims and Claims Adjustment Expense [Line Items] |  |  |  |  |  |  |  |
Net Prior Period Development |  | $ (68) | $ (67) | $ (71) |  |  |  |
Prior Period Development, net Adjustments |  | 0 |  |  |  |  |  |
Overseas General Insurance | Short Tail [Member] |  |  |  |  |  |  |  |
Liability for Claims and Claims Adjustment Expense [Line Items] |  |  |  |  |  |  |  |
Net Prior Period Development |  | (24) | (145) | (181) |  |  |  |
Prior Period Development, net Adjustments |  | 1 |  |  |  |  |  |
Overseas General Insurance | Other [Member] | Long Tail [Member] |  |  |  |  |  |  |  |
Liability for Claims and Claims Adjustment Expense [Line Items] |  |  |  |  |  |  |  |
Net Prior Period Development |  |  | (32) |  |  |  |  |
Overseas General Insurance | Casualty Lines [Member] | Long Tail [Member] |  |  |  |  |  |  |  |
Liability for Claims and Claims Adjustment Expense [Line Items] |  |  |  |  |  |  |  |
Net Prior Period Development |  | (101) |  |  |  |  |  |
Overseas General Insurance | Financial [Member] | Long Tail [Member] |  |  |  |  |  |  |  |
Liability for Claims and Claims Adjustment Expense [Line Items] |  |  |  |  |  |  |  |
Net Prior Period Development |  | 52 | 38 |  |  |  |  |
Overseas General Insurance | Casualty [Member] | Long Tail [Member] |  |  |  |  |  |  |  |
Liability for Claims and Claims Adjustment Expense [Line Items] |  |  |  |  |  |  |  |
Net Prior Period Development |  |  | (70) |  |  |  |  |
Overseas General Insurance | Aviation [Member] | Long Tail [Member] |  |  |  |  |  |  |  |
Liability for Claims and Claims Adjustment Expense [Line Items] |  |  |  |  |  |  |  |
Net Prior Period Development |  |  | (10) |  |  |  |  |
Overseas General Insurance | Political [Member] | Long Tail [Member] |  |  |  |  |  |  |  |
Liability for Claims and Claims Adjustment Expense [Line Items] |  |  |  |  |  |  |  |
Net Prior Period Development |  |  | (12) |  |  |  |  |
Overseas General Insurance | Accident years 2015 through 2017 [Member] | Financial [Member] | Long Tail [Member] |  |  |  |  |  |  |  |
Liability for Claims and Claims Adjustment Expense [Line Items] |  |  |  |  |  |  |  |
Net Prior Period Development |  |  | 131 |  |  |  |  |
Overseas General Insurance | Accident years 2015 through 2017 [Member] | Casualty [Member] | Long Tail [Member] |  |  |  |  |  |  |  |
Liability for Claims and Claims Adjustment Expense [Line Items] |  |  |  |  |  |  |  |
Net Prior Period Development |  |  | 38 |  |  |  |  |
Overseas General Insurance | Accident years 2015 through 2017 [Member] | Accident and Health [Member] | Short Tail [Member] |  |  |  |  |  |  |  |
Liability for Claims and Claims Adjustment Expense [Line Items] |  |  |  |  |  |  |  |
Net Prior Period Development |  |  | (33) |  |  |  |  |
Overseas General Insurance | Accident years 2013 - 2016 [Member] | Property and Inland Marine [Member] | Short Tail [Member] |  |  |  |  |  |  |  |
Liability for Claims and Claims Adjustment Expense [Line Items] |  |  |  |  |  |  |  |
Net Prior Period Development |  |  | (99) |  |  |  |  |
Overseas General Insurance | Accident years 2014 and prior [Member] | Financial [Member] | Long Tail [Member] |  |  |  |  |  |  |  |
Liability for Claims and Claims Adjustment Expense [Line Items] |  |  |  |  |  |  |  |
Net Prior Period Development |  |  | (93) |  |  |  |  |
Overseas General Insurance | Accident years 2014 and prior [Member] | Casualty [Member] | Long Tail [Member] |  |  |  |  |  |  |  |
Liability for Claims and Claims Adjustment Expense [Line Items] |  |  |  |  |  |  |  |
Net Prior Period Development |  |  | (107) |  |  |  |  |
Overseas General Insurance | Accident years 2017 - 2018 [Member] | Credit-related [Member] | Short Tail [Member] |  |  |  |  |  |  |  |
Liability for Claims and Claims Adjustment Expense [Line Items] |  |  |  |  |  |  |  |
Net Prior Period Development |  | 27 |  |  |  |  |  |
Overseas General Insurance | Accident years 2017 - 2018 [Member] | Accident and Health [Member] | Short Tail [Member] |  |  |  |  |  |  |  |
Liability for Claims and Claims Adjustment Expense [Line Items] |  |  |  |  |  |  |  |
Net Prior Period Development |  | (45) |  |  |  |  |  |
Overseas General Insurance | Short-duration Insurance Contracts, Accident Year 2018 [Member] | Construction [Member] | Short Tail [Member] |  |  |  |  |  |  |  |
Liability for Claims and Claims Adjustment Expense [Line Items] |  |  |  |  |  |  |  |
Net Prior Period Development |  | 23 |  |  |  |  |  |
Overseas General Insurance | Accident years 2016 and prior [Member] | Marine [Member] | Short Tail [Member] |  |  |  |  |  |  |  |
Liability for Claims and Claims Adjustment Expense [Line Items] |  |  |  |  |  |  |  |
Net Prior Period Development |  | (36) |  |  |  |  |  |
Overseas General Insurance | Accident Year 2015 and prior [Member] | Casualty Lines [Member] | Long Tail [Member] |  |  |  |  |  |  |  |
Liability for Claims and Claims Adjustment Expense [Line Items] |  |  |  |  |  |  |  |
Net Prior Period Development |  | (123) |  |  |  |  |  |
Overseas General Insurance | Accident Year 2015 and prior [Member] | Financial [Member] | Long Tail [Member] |  |  |  |  |  |  |  |
Liability for Claims and Claims Adjustment Expense [Line Items] |  |  |  |  |  |  |  |
Net Prior Period Development |  | (75) |  |  |  |  |  |
Overseas General Insurance | Accident years 2016 - 2018 [Member] | Casualty Lines [Member] | Long Tail [Member] |  |  |  |  |  |  |  |
Liability for Claims and Claims Adjustment Expense [Line Items] |  |  |  |  |  |  |  |
Net Prior Period Development |  | 22 |  |  |  |  |  |
Overseas General Insurance | Accident years 2016 - 2018 [Member] | Financial [Member] | Long Tail [Member] |  |  |  |  |  |  |  |
Liability for Claims and Claims Adjustment Expense [Line Items] |  |  |  |  |  |  |  |
Net Prior Period Development |  | $ 127 |  |  |  |  |  |
Overseas General Insurance - Casualty [Member] | Europe [Member] |  |  |  |  |  |  |  |
Liability for Claims and Claims Adjustment Expense [Line Items] |  |  |  |  |  |  |  |
Loss by Geographic Percentage |  | 45.00% |  |  |  |  |  |
Overseas General Insurance - Non-Casualty [Member] | Latin America [Member] |  |  |  |  |  |  |  |
Liability for Claims and Claims Adjustment Expense [Line Items] |  |  |  |  |  |  |  |
Loss by Geographic Percentage |  | 30.00% |  |  |  |  |  |
Overseas General Insurance - Non-Casualty [Member] | Europe [Member] |  |  |  |  |  |  |  |
Liability for Claims and Claims Adjustment Expense [Line Items] |  |  |  |  |  |  |  |
Loss by Geographic Percentage |  | 30.00% |  |  |  |  |  |
Global Reinsurance Non-Casualty [Member] | Accident year 2010 and after [Member] |  |  |  |  |  |  |  |
Liability for Claims and Claims Adjustment Expense [Line Items] |  |  |  |  |  |  |  |
Loss by Geographic Percentage |  | 73.00% |  |  |  |  |  |
Global Reinsurance Non-Casualty [Member] | Accident years 2010 to 2012 [Member] |  |  |  |  |  |  |  |
Liability for Claims and Claims Adjustment Expense [Line Items] |  |  |  |  |  |  |  |
Loss by Geographic Percentage |  | 58.00% |  |  |  |  |  |
Global Reinsurance Non-Casualty [Member] | Accident years 2013 to 2019 [Member] |  |  |  |  |  |  |  |
Liability for Claims and Claims Adjustment Expense [Line Items] |  |  |  |  |  |  |  |
Loss by Geographic Percentage |  | 80.00% |  |  |  |  |  |
Segment Global Reinsurance [Member] |  |  |  |  |  |  |  |
Liability for Claims and Claims Adjustment Expense [Line Items] |  |  |  |  |  |  |  |
Net Prior Period Development |  | $ (29) | $ (50) | $ (59) |  |  |  |
Prior Period Development, net Adjustments |  | $ (1) |  |  |  |  |  |
Prior Period Development Percentage Opening Net Unpaid Reserves | [1] | 0.10% | 0.10% | 0.10% |  |  |  |
Segment Global Reinsurance [Member] | Long Tail [Member] |  |  |  |  |  |  |  |
Liability for Claims and Claims Adjustment Expense [Line Items] |  |  |  |  |  |  |  |
Net Prior Period Development |  | $ (59) | $ (69) | $ (68) |  |  |  |
Prior Period Development, net Adjustments |  | 0 |  |  |  |  |  |
Segment Global Reinsurance [Member] | Short Tail [Member] |  |  |  |  |  |  |  |
Liability for Claims and Claims Adjustment Expense [Line Items] |  |  |  |  |  |  |  |
Net Prior Period Development |  | 30 | 19 | 9 |  |  |  |
Prior Period Development, net Adjustments |  | (1) |  |  |  |  |  |
Segment Global Reinsurance [Member] | Accident Year 2013 and prior [Member] | Other [Member] | Long Tail [Member] |  |  |  |  |  |  |  |
Liability for Claims and Claims Adjustment Expense [Line Items] |  |  |  |  |  |  |  |
Net Prior Period Development |  | (59) | (69) |  |  |  |  |
Segment Global Reinsurance [Member] | Accident years 2017 - 2018 [Member] | Catastrophe [Member] | Short Tail [Member] |  |  |  |  |  |  |  |
Liability for Claims and Claims Adjustment Expense [Line Items] |  |  |  |  |  |  |  |
Net Prior Period Development |  | 44 |  |  |  |  |  |
Segment Global Reinsurance [Member] | Short-duration Insurance Contracts, Accident Year 2017 [Member] | Catastrophe [Member] | Short Tail [Member] |  |  |  |  |  |  |  |
Liability for Claims and Claims Adjustment Expense [Line Items] |  |  |  |  |  |  |  |
Net Prior Period Development |  |  | 18 |  |  |  |  |
Corporate Segment [Member] |  |  |  |  |  |  |  |
Liability for Claims and Claims Adjustment Expense [Line Items] |  |  |  |  |  |  |  |
Net Prior Period Development |  | $ 153 | $ 45 | $ 278 |  |  |  |
Prior Period Development Percentage Opening Net Unpaid Reserves | [1] | 0.30% | 0.10% | 0.60% |  |  |  |
Corporate Segment [Member] | Discontinued Operations [Member] |  |  |  |  |  |  |  |
Liability for Claims and Claims Adjustment Expense [Line Items] |  |  |  |  |  |  |  |
Net Prior Period Development |  | $ 37 |  |  |  |  |  |
Corporate Segment [Member] | Long Tail [Member] |  |  |  |  |  |  |  |
Liability for Claims and Claims Adjustment Expense [Line Items] |  |  |  |  |  |  |  |
Net Prior Period Development |  | 153 | $ 45 | $ 278 |  |  |  |
Prior Period Development, net Adjustments |  | 0 |  |  |  |  |  |
Corporate Segment [Member] | Long Tail [Member] | Discontinued Operations [Member] |  |  |  |  |  |  |  |
Liability for Claims and Claims Adjustment Expense [Line Items] |  |  |  |  |  |  |  |
Net Prior Period Development |  |  | 35 |  |  |  |  |
Corporate Segment [Member] | Long Tail [Member] | Reinsurance, Structured Settlements [Member] |  |  |  |  |  |  |  |
Liability for Claims and Claims Adjustment Expense [Line Items] |  |  |  |  |  |  |  |
Net Prior Period Development |  |  | (205) |  |  |  |  |
Corporate Segment [Member] | Short Tail [Member] |  |  |  |  |  |  |  |
Liability for Claims and Claims Adjustment Expense [Line Items] |  |  |  |  |  |  |  |
Net Prior Period Development |  | 0 | 0 | $ 0 |  |  |  |
Corporate Segment [Member] | Asbestos & Environmental [Member] | Long Tail [Member] |  |  |  |  |  |  |  |
Liability for Claims and Claims Adjustment Expense [Line Items] |  |  |  |  |  |  |  |
Net Prior Period Development |  | $ 116 | 216 |  |  |  |  |
Environmental Issue [Member] | Overseas General Insurance | Long Tail [Member] |  |  |  |  |  |  |  |
Liability for Claims and Claims Adjustment Expense [Line Items] |  |  |  |  |  |  |  |
Net Prior Period Development |  |  | $ (10) |  |  |  |  |
[1] | Calculated based on the beginning of period consolidated net unpaid losses and loss expenses.

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