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Debt (Schedule of Debt Outstanding) (Details) € in Millions, $ in Millions | Dec. 31, 2023 USD ($) | Dec. 31, 2023 EUR (€) | Dec. 31, 2022 USD ($) | Mar. 31, 2000 USD ($)
--- | --- | --- | --- | ---
Debt Instrument [Line Items] |  |  |  |  |
Repurchase agreements |  | $ 2,833 |  | $ 1,419 |
Short-term debt |  | 1,460 |  | 475 |
Long-term debt |  | 13,035 |  | 14,402 |
Variable Interest Entity, Primary Beneficiary |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |
Repurchase agreements |  | 1,009 |  | 0 |
Senior Notes | INA Senior Notes Due May 2024 [Member] |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |
Debt Instrument, Face Amount |  | $ 700 |  |  |
Long-term debt stated interest rate |  | 3.35% | 3.35% |  |
Long-term debt |  | $ 0 |  | 699 |
Make Whole Premium Additional Percent |  | 0.15% | 0.15% |  |
Senior Notes | INA Senior Notes Due December 2024 [Member] |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |
Debt Instrument, Face Amount | € |  |  | € 700 |  |
Long-term debt stated interest rate |  | 0.30% | 0.30% |  |
Long-term debt |  | $ 0 |  | 742 |
Make Whole Premium Additional Percent |  | 0.15% | 0.15% |  |
Senior Notes | INA Senior Notes Due March 2025 [Member] |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |
Debt Instrument, Face Amount |  | $ 800 |  |  |
Long-term debt stated interest rate |  | 3.15% | 3.15% |  |
Long-term debt |  | $ 799 |  | 798 |
Make Whole Premium Additional Percent |  | 0.15% | 0.15% |  |
Senior Notes | INA Senior Notes Due May 2026 [Member] |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |
Debt Instrument, Face Amount |  | $ 1,500 |  |  |
Long-term debt stated interest rate |  | 3.35% | 3.35% |  |
Long-term debt |  | $ 1,497 |  | 1,496 |
Make Whole Premium Additional Percent |  | 0.20% | 0.20% |  |
Senior Notes | INA Senior Notes Due June 2027 [Member] |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |
Debt Instrument, Face Amount | € |  |  | € 575 |  |
Long-term debt stated interest rate |  | 0.875% | 0.875% |  |
Long-term debt |  | $ 623 |  | 609 |
Make Whole Premium Additional Percent |  | 0.20% | 0.20% |  |
Senior Notes | INA Senior Notes Due March 2028 [Member] |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |
Debt Instrument, Face Amount | € |  |  | € 900 |  |
Long-term debt stated interest rate |  | 1.55% | 1.55% |  |
Long-term debt |  | $ 974 |  | 952 |
Make Whole Premium Additional Percent |  | 0.15% | 0.15% |  |
Senior Notes | INA Senior Notes Due December 2029 [Member] |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |
Debt Instrument, Face Amount | € |  |  | € 700 |  |
Long-term debt stated interest rate |  | 0.875% | 0.875% |  |
Long-term debt |  | $ 758 |  | 740 |
Make Whole Premium Additional Percent |  | 0.20% | 0.20% |  |
Senior Notes | INA Senior Notes Due September 2030 [Member] |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |
Debt Instrument, Face Amount |  | $ 1,000 |  |  |
Long-term debt stated interest rate |  | 1.375% | 1.375% |  |
Long-term debt |  | $ 994 |  | 993 |
Make Whole Premium Additional Percent |  | 0.15% | 0.15% |  |
Senior Notes | INA Senior Notes Due June 2031 [Member] |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |
Debt Instrument, Face Amount | € |  |  | € 575 |  |
Long-term debt stated interest rate |  | 1.40% | 1.40% |  |
Long-term debt |  | $ 621 |  | 606 |
Make Whole Premium Additional Percent |  | 0.25% | 0.25% |  |
Senior Notes | INA Senior Notes Due May 2036 [Member] |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |
Debt Instrument, Face Amount |  | $ 300 |  |  |
Long-term debt stated interest rate |  | 6.70% | 6.70% |  |
Long-term debt |  | $ 298 |  | 298 |
Make Whole Premium Additional Percent |  | 0.20% | 0.20% |  |
Senior Notes | INA Senior Notes Due May 2037 [Member] |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |
Debt Instrument, Face Amount |  | $ 800 |  |  |
Long-term debt stated interest rate |  | 6.00% | 6.00% |  |
Long-term debt |  | $ 918 |  | 927 |
Make Whole Premium Additional Percent |  | 0.20% | 0.20% |  |
Senior Notes | INA Senior Notes Due March 2038 [Member] |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |
Debt Instrument, Face Amount | € |  |  | € 900 |  |
Long-term debt stated interest rate |  | 2.50% | 2.50% |  |
Long-term debt |  | $ 971 |  | 949 |
Make Whole Premium Additional Percent |  | 0.25% | 0.25% |  |
Senior Notes | INA Senior Notes Due May 2038 [Member] |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |
Debt Instrument, Face Amount |  | $ 600 |  |  |
Long-term debt stated interest rate |  | 6.50% | 6.50% |  |
Long-term debt |  | $ 718 |  | 726 |
Make Whole Premium Additional Percent |  | 0.30% | 0.30% |  |
Senior Notes | INA Senior Notes Due March 2043 [Member] |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |
Debt Instrument, Face Amount |  | $ 475 |  |  |
Long-term debt stated interest rate |  | 4.15% | 4.15% |  |
Long-term debt |  | $ 471 |  | 471 |
Make Whole Premium Additional Percent |  | 0.15% | 0.15% |  |
Senior Notes | INA Senior Notes Due November 2045 [Member] |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |
Debt Instrument, Face Amount |  | $ 1,500 |  |  |
Long-term debt stated interest rate |  | 4.35% | 4.35% |  |
Long-term debt |  | $ 1,486 |  | 1,485 |
Make Whole Premium Additional Percent |  | 0.25% | 0.25% |  |
Senior Notes | INA Senior Notes Due December 2051 [Member] |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |
Debt Instrument, Face Amount |  | $ 600 |  |  |
Long-term debt stated interest rate |  | 2.85% | 2.85% |  |
Long-term debt |  | $ 593 |  | 593 |
Make Whole Premium Additional Percent |  | 0.15% | 0.15% |  |
Senior Notes | INA Senior Notes Due December 2061 [Member] |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |
Debt Instrument, Face Amount |  | $ 1,000 |  |  |
Long-term debt stated interest rate |  | 3.05% | 3.05% |  |
Long-term debt |  | $ 984 |  | 984 |
Make Whole Premium Additional Percent |  | 0.20% | 0.20% |  |
Trust Preferred Securities | Chubb INA Capital Securities Due 2030 [Member] |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |
Debt Instrument, Face Amount |  | $ 309 |  |  | $ 300
Long-term debt stated interest rate |  | 9.70% | 9.70% |  | 9.70%
Trust preferred securities | [1] | $ 308 |  | 308 |
Unsecured Debt | INA Senior Notes Due August 2029 [Member] |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |
Debt Instrument, Face Amount |  | $ 100 |  |  |
Long-term debt stated interest rate |  | 8.875% | 8.875% |  |
Long-term debt |  | $ 100 |  | 100 |
Unsecured Debt | INA Senior Notes Due November 2031 [Member] |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |
Debt Instrument, Face Amount |  | $ 200 |  |  |
Long-term debt stated interest rate |  | 6.80% | 6.80% |  |
Long-term debt |  | $ 230 |  | $ 234 |
Make Whole Premium Additional Percent |  | 0.25% | 0.25% |  |
Repurchase agreements |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |
Weighted average interest rate on short-term debt |  | 5.40% | 5.40% | 3.90% |
Repurchase agreements |  | $ 1,824 |  | $ 1,419 |
Repurchase agreements | Variable Interest Entity, Primary Beneficiary |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |
Weighted average interest rate on short-term debt |  | 4.90% | 4.90% |  |
Repurchase agreements | [2] | $ 1,009 |  | 0 |
Senior Notes | INA Senior Notes Due March 2023 [Member] |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |
Debt Instrument, Face Amount |  | $ 475 |  |  |
Long-term debt stated interest rate |  | 2.70% | 2.70% |  |
Short-term debt |  | $ 0 |  | 475 |
Make Whole Premium Additional Percent |  | 0.10% | 0.10% |  |
Senior Notes | INA Senior Notes Due May 2024 [Member] |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |
Debt Instrument, Face Amount |  | $ 700 |  |  |
Long-term debt stated interest rate |  | 3.35% | 3.35% |  |
Short-term debt |  | $ 700 |  | 0 |
Make Whole Premium Additional Percent |  | 0.15% | 0.15% |  |
Senior Notes | INA Senior Notes Due December 2024 [Member] |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |
Debt Instrument, Face Amount |  | $ 700 |  |  |
Long-term debt stated interest rate |  | 0.30% | 0.30% |  |
Short-term debt |  | $ 760 |  | $ 0 |
Make Whole Premium Additional Percent |  | 0.15% | 0.15% |  |
[1] | Redemption prices are equal to accrued and unpaid interest to the redemption date plus the greater of (i) 100 percent of the principal amount thereof, or (ii) sum of present value of scheduled payments of principal and interest on the capital securities from the redemption date to April 1, 2030
[2] | Refer to Note 1 g) to the Consolidated Financial Statements for additional information on the consolidation of VIEs.

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- Definition Weighted average interest rate of short-term debt outstanding calculated at point in time. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.19(b)) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480566/210-10-S99-1 + Details
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