Repurchase Agreements (Borrowings Under Repurchase Agreement) (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Debt Securities, Available-for-sale [Line Items]
Balance of repurchase agreements	$ 7,768,180	$ 9,139,821
Repurchase Agreement Borrowings
Debt Securities, Available-for-sale [Line Items]
Balance of repurchase agreements	$ 7,768,991	$ 9,140,944
Weighted Average Interest Rate	3.14%	2.99%
Less debt issuance costs	$ 811	$ 1,123
Total repurchase agreements less debt issuance costs	7,768,180	9,139,821
Repurchase Agreement Borrowings \| Within 30 days
Debt Securities, Available-for-sale [Line Items]
Balance of repurchase agreements	$ 2,504,628	$ 4,472,120
Weighted Average Interest Rate	1.96%	2.55%
Repurchase Agreement Borrowings \| Over 30 days to 3 months
Debt Securities, Available-for-sale [Line Items]
Balance of repurchase agreements	$ 2,993,905	$ 2,746,384
Weighted Average Interest Rate	2.96%	3.43%
Repurchase Agreement Borrowings \| Over 3 months to 12 months
Debt Securities, Available-for-sale [Line Items]
Balance of repurchase agreements	$ 1,392,318	$ 1,014,441
Weighted Average Interest Rate	4.06%	3.36%
Repurchase Agreement Borrowings \| Over 12 months
Debt Securities, Available-for-sale [Line Items]
Balance of repurchase agreements	$ 878,140	$ 907,999
Weighted Average Interest Rate	5.65%	3.44%

Securities Sold Under Agreements To Repurchase, Net of Debt Issuance Costs

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- Definition

Interest rate on the amount to be repaid to the counterparty to the repurchase agreement when the carrying amount (or market value, if higher than the carrying amount) of securities or other assets sold under the repurchase agreement exceeds 10 percent of total assets.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
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+ References

No definition available.

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- Definition

Amount, after the effects of master netting arrangements, of funds outstanding borrowed in the form of a security repurchase agreement between the entity and another party for the sale and repurchase of identical or substantially the same securities at a date certain for a specified price. Includes liabilities not subject to a master netting arrangement and not elected to be offset.

+ References

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- Definition

The remaining balance of debt issuance expenses that were capitalized and are being amortized against income over the lives of the respective bond issues. This does not include the amounts capitalized as part of the cost of the utility plant or asset.

+ References

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