Pledged Assets (Assets Pledged from Counterparties) (Details) - USD ($) $ in Thousands	Jun. 30, 2026	Dec. 31, 2025	Jun. 30, 2025
Offsetting Assets and Liabilities [Line Items]
Obligation to Return Securities Borrowed Under Reverse Repurchase Agreements at Fair Value	$ 18,150,000	$ 16,452,000
Restricted Cash and Cash Equivalent	1,329,000	1,292,000	$ 1,216,000
Assets Pledged to Us [Member]
Offsetting Assets and Liabilities [Line Items]
Restricted Cash and Cash Equivalent	131,000	119,000
Restricted Cash and Securities Pledged	18,431,000	16,591,000
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member] \| Assets Pledged to Us [Member]
Offsetting Assets and Liabilities [Line Items]
Pledged Financial Instruments, Not Separately Reported, Mortgage-Related Securities Available-for-sale or Held-for-investment	(21,000)	(10,000)
Restricted Cash and Cash Equivalent	31,000	19,000
Securities Sold under Agreements to Repurchase [Member] \| Assets Pledged to Us [Member]
Offsetting Assets and Liabilities [Line Items]
Pledged Financial Instruments, Not Separately Reported, Mortgage-Related Securities Available-for-sale or Held-for-investment	(89,000)	(62,000)
Derivative [Member] \| Assets Pledged to Us [Member]
Offsetting Assets and Liabilities [Line Items]
Restricted Cash and Securities Pledged	100,000	100,000
US Treasury Securities [Member] \| Assets Pledged to Us [Member]
Offsetting Assets and Liabilities [Line Items]
Pledged Financial Instruments, Not Separately Reported, Mortgage-Related Securities Available-for-sale or Held-for-investment	(18,263,000)	(16,439,000)
Reverse Repurchase Agreements [Member] \| Assets Pledged to Us [Member]
Offsetting Assets and Liabilities [Line Items]
Pledged Financial Instruments, Not Separately Reported, Mortgage-Related Securities Available-for-sale or Held-for-investment	(18,242,000)	(16,429,000)
Agency Securities [Member]
Offsetting Assets and Liabilities [Line Items]
Pledged Financial Instruments, Not Separately Reported, Mortgage-Related Securities Available-for-sale or Held-for-investment	(80,761,000)	(74,149,000)
Agency Securities [Member] \| Assets Pledged to Us [Member]
Offsetting Assets and Liabilities [Line Items]
Pledged Financial Instruments, Not Separately Reported, Mortgage-Related Securities Available-for-sale or Held-for-investment	(37,000)	(33,000)
Reverse Repurchase Agreements [Member] \| US Treasury Securities [Member] \| Assets Pledged to Us [Member]
Offsetting Assets and Liabilities [Line Items]
Pledged Financial Instruments, Not Separately Reported, Mortgage-Related Securities Available-for-sale or Held-for-investment	(18,242,000)	(16,429,000)
Derivative [Member] \| US Treasury Securities [Member] \| Assets Pledged to Us [Member]
Offsetting Assets and Liabilities [Line Items]
Pledged Financial Instruments, Not Separately Reported, Mortgage-Related Securities Available-for-sale or Held-for-investment	0	0
Repurchase Agreements [Member] \| Agency Securities [Member] \| Assets Pledged to Us [Member]
Offsetting Assets and Liabilities [Line Items]
Pledged Financial Instruments, Not Separately Reported, Mortgage-Related Securities Available-for-sale or Held-for-investment	(37,000)	(33,000)
Derivative [Member] \| Assets Pledged to Us [Member]
Offsetting Assets and Liabilities [Line Items]
Restricted Cash and Cash Equivalent	100,000	100,000
Reverse Repurchase Agreements [Member] \| Assets Pledged to Us [Member]
Offsetting Assets and Liabilities [Line Items]
Restricted Cash and Cash Equivalent	$ 0	$ 0