Derivative Instruments and Hedging Activities U.S. Treasury Futures (Details) - USD ($) |
Dec. 31, 2019 |
Dec. 31, 2018 |
Dec. 31, 2017 |
|---|---|---|---|
| Derivative [Line Items] | |||
| Notional | $ 49,205,497,000 | $ 36,528,169,000 | $ 31,226,878,000 |
| Derivative Financial Instruments, Assets [Member] | |||
| Derivative [Line Items] | |||
| Notional | 14,343,137,000 | 36,258,904,000 | |
| Fair Value | 188,051,000 | $ 319,981,000 | |
| U.S. Treasury Futures [Member] | |||
| Derivative [Line Items] | |||
| Notional | 380,000,000.0 | ||
| U.S. Treasury Futures [Member] | Derivative Financial Instruments, Assets [Member] | |||
| Derivative [Line Items] | |||
| Notional | 380,000,000 | ||
| Fair Value | $ 502,000 |
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- Definition Fair value of the assets less the liabilities of a derivative or group of derivatives. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
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- Definition Nominal or face amount used to calculate payment on derivative. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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