Borrowings (Summary Of Advances Payable To the Federal Home Loan Bank) (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Federal Home Loan Bank, Advances, Maturity, Rolling Year [Abstract]
FHLB advances maturing within 1 year, Total Outstanding	$ 3,650,000	$ 2,350,000
FHLB advances maturing after 1 but within 2 years, Total Outstanding	0	0
FHLB advances maturing after 2 but within 3 years, Total Outstanding	0	0
FHLB advances maturing after 3 but within 4 years, Total Outstanding	456	235
FHLB advances maturing after 4 but within 5 years, Total Outstanding	0	228
FHLB advances maturing after 5 years, Total Outstanding	9,474	9,555
Total FHLB advances	$ 3,659,930	$ 2,360,018
Federal Home Loan Bank, Advances, Weighted Average Interest Rate [Abstract]
FHLB advances maturing within 1 year, Weighted Average Contractual Coupon Rate (as a percent)	5.50%	5.53%
FHLB advances maturing after 1 but within 2 years, Weighted Average Contractual Coupon Rate (as a percent)	0.00%	0.00%
FHLB advances maturing after 2 but within 3 years, Weighted Average Contractual Coupon Rate (as a percent)	0.00%	0.00%
FHLB advances maturing after 3 but within 4 years, Weighted Average Contractual Coupon Rate (as a percent)	1.36%	0.00%
FHLB advances maturing after 4 but within 5 years, Weighted Average Contractual Coupon Rate (as a percent)	0.00%	2.75%
FHLB advances maturing after 5 years, Weighted Average Contractual Coupon Rate (as a percent)	2.08%	2.07%
Federal Home Loan Bank, Advances, Weighted Average Contractual Coupon Rate (as a percent)	5.49%	5.52%
Aggregate market value of assets pledged as collateral	$ 20,238,325	$ 20,734,035
Remaining borrowing capacity at FHLB	$ 10,779,412	$ 12,535,423

Amount of assets pledged to secure a debt instrument.

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-Name Accounting Standards Codification
-Topic 942
-SubTopic 470
-Section 50
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Amount of advances from the Federal Home Loan Bank (FHLB).

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Amount of advances or credit lines available from the Federal Home Loan Bank (FHLB).

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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Amount of advances from Federal Home Loan Bank (FHLBank) maturing after the fifth rolling twelve months following the latest balance sheet. For interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount of advances from Federal Home Loan Bank (FHLBank) maturing in the fourth rolling twelve months following the latest balance sheet. For interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount of advances from Federal Home Loan Bank (FHLBank) maturing in the third rolling twelve months following the latest balance sheet. For interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount of advances from Federal Home Loan Bank (FHLBank) maturing in the second rolling twelve months following the latest balance sheet. For interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Weighted average interest rate on advances made and reported by Federal Home Loan Bank (FHLBank).

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Weighted average interest rate on advances made and reported by Federal Home Loan Bank (FHLBank) maturing in the next rolling twelve months following the latest balance sheet. For interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Weighted average interest rate on advances made and reported by Federal Home Loan Bank (FHLBank) maturing in the fifth rolling twelve months following the latest balance sheet. For interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Weighted average interest rate on advances made and reported by Federal Home Loan Bank (FHLBank) maturing in the fourth rolling twelve months following the latest balance sheet. For interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Weighted average interest rate on advances made and reported by Federal Home Loan Bank maturing in the third rolling twelve months following the latest balance sheet. For interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Weighted average interest rate on advances made and reported by Federal Home Loan Bank (FHLBank) maturing in the second rolling twelve months following the latest balance sheet. For interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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