Derivative Instruments and Hedging Activities Short U.S. Treasury Securities (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, Liabilities [Member] | |||
| Derivative [Line Items] | |||
| Notional | 34,862,360,000 | 5,403,265,000 | |
| Fair Value | $ (6,740,000) | (820,590,000) | |
| Short US Treasuries [Member] | |||
| Derivative [Line Items] | |||
| Fair Value | 781,500,000 | ||
| Short US Treasuries [Member] | Derivative Financial Instruments, Liabilities [Member] | |||
| Derivative [Line Items] | |||
| Notional | 800,000,000.0 | ||
| Fair Value | $ (781,455,000) |
| X | ||||||||||
- 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
|
| X | ||||||||||
- 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.
|
| X | ||||||||||
- Definition Nominal or face amount used to calculate payment on derivative. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|