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Derivative Instruments - Fair value and notional amount of derivatives (Details) - USD ($) $ in Thousands | Sep. 30, 2021 | Dec. 31, 2020
--- | --- | ---
Derivative offsetting |  |  |
Derivative assets subject to master netting agreements |  | $ 133,100 | $ 138,800
Derivative liabilities subject to master netting agreements |  | 42,200 | 93,000
Not designated as hedging instrument |  |  |
Derivative [Line Items] |  |  |
Asset derivatives - fair value |  | 139,185 | 177,383
Liability derivatives - fair value |  | (43,526) | (108,705)
Not designated as hedging instrument | Futures contracts |  |  |
Derivative [Line Items] |  |  |
Net derivatives - notional value | [1],[2] | 2,796,442 | 3,099,796
Not designated as hedging instrument | Futures contracts | Other assets |  |  |
Derivative [Line Items] |  |  |
Asset derivatives - fair value | [2] | 36,010 | 11,046
Not designated as hedging instrument | Futures contracts | Other liabilities |  |  |
Derivative [Line Items] |  |  |
Liability derivatives - fair value | [2] | (17,562) | (4,496)
Not designated as hedging instrument | Foreign currency forward contracts |  |  |
Derivative [Line Items] |  |  |
Net derivatives - notional value | [1],[2] | 1,234,665 | 1,656,729
Not designated as hedging instrument | Foreign currency forward contracts | Other assets |  |  |
Derivative [Line Items] |  |  |
Asset derivatives - fair value | [2] | 7,380 | 52,716
Not designated as hedging instrument | Foreign currency forward contracts | Other liabilities |  |  |
Derivative [Line Items] |  |  |
Liability derivatives - fair value | [2] | (13,914) | (6,202)
Not designated as hedging instrument | TBAs |  |  |
Derivative [Line Items] |  |  |
Net derivatives - notional value | [1],[3] | 47,603 | 0
Not designated as hedging instrument | TBAs | Fixed maturities available for sale |  |  |
Derivative [Line Items] |  |  |
Asset derivatives - fair value | [3] | 49,227 | 0
Liability derivatives - fair value | [3] | 0 | 0
Not designated as hedging instrument | Other |  |  |
Derivative [Line Items] |  |  |
Net derivatives - notional value | [1],[2] | 4,184,225 | 5,763,919
Not designated as hedging instrument | Other | Other assets |  |  |
Derivative [Line Items] |  |  |
Asset derivatives - fair value | [2] | 46,568 | 113,621
Not designated as hedging instrument | Other | Other liabilities |  |  |
Derivative [Line Items] |  |  |
Liability derivatives - fair value | [2] | $ (12,050) | $ (98,007)
[1] | Represents the absolute notional value of all outstanding contracts, consisting of long and short positions.
[2] | The fair value of asset derivatives are included in ‘other assets’ and the fair value of liability derivatives are included in ‘other liabilities.’
[3] | The fair value of TBAs are included in ‘fixed maturities available forsale, at fair value.’

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