Annual report pursuant to Section 13 and 15(d)

Schedule of Repurchase Agreements by Maturity (Details)

v3.20.4
Schedule of Repurchase Agreements by Maturity (Details) - USD ($)
$ in Thousands
Dec. 31, 2020
Dec. 31, 2019
Assets Sold under Agreements to Repurchase [Line Items]    
Repurchase agreements $ 15,143,898 $ 29,147,463
Weighted average borrowing rate 0.28% 2.14%
US Government Agencies Debt Securities [Member]    
Assets Sold under Agreements to Repurchase [Line Items]    
Repurchase agreements $ 15,089,726 $ 27,302,527
Weighted average borrowing rate 0.28% 2.08%
Mortgage-backed Securities, Issued by Private Enterprises [Member]    
Assets Sold under Agreements to Repurchase [Line Items]    
Repurchase agreements $ 1,899 $ 1,531,607
Weighted average borrowing rate 2.33% 2.90%
Inverse Interest-Only Securities [Member]    
Assets Sold under Agreements to Repurchase [Line Items]    
Repurchase agreements $ 52,273 $ 50,714
Weighted average borrowing rate 0.89% 2.70%
Mortgage servicing rights    
Assets Sold under Agreements to Repurchase [Line Items]    
Repurchase agreements $ 0 $ 262,615
Weighted average borrowing rate 0.00% 3.51%
Maturity up to 30 days [Member]    
Assets Sold under Agreements to Repurchase [Line Items]    
Repurchase agreements $ 5,370,506 $ 5,305,916
Maturity up to 30 days [Member] | US Government Agencies Debt Securities [Member]    
Assets Sold under Agreements to Repurchase [Line Items]    
Repurchase agreements 5,330,627 5,112,681
Maturity up to 30 days [Member] | Mortgage-backed Securities, Issued by Private Enterprises [Member]    
Assets Sold under Agreements to Repurchase [Line Items]    
Repurchase agreements 1,271 193,235
Maturity up to 30 days [Member] | Inverse Interest-Only Securities [Member]    
Assets Sold under Agreements to Repurchase [Line Items]    
Repurchase agreements 38,608 0
Maturity up to 30 days [Member] | Mortgage servicing rights    
Assets Sold under Agreements to Repurchase [Line Items]    
Repurchase agreements 0 0
Maturity 30 to 59 Days [Member]    
Assets Sold under Agreements to Repurchase [Line Items]    
Repurchase agreements 4,292,861 6,300,372
Maturity 30 to 59 Days [Member] | US Government Agencies Debt Securities [Member]    
Assets Sold under Agreements to Repurchase [Line Items]    
Repurchase agreements 4,292,861 6,074,151
Maturity 30 to 59 Days [Member] | Mortgage-backed Securities, Issued by Private Enterprises [Member]    
Assets Sold under Agreements to Repurchase [Line Items]    
Repurchase agreements 0 212,998
Maturity 30 to 59 Days [Member] | Inverse Interest-Only Securities [Member]    
Assets Sold under Agreements to Repurchase [Line Items]    
Repurchase agreements 0 13,223
Maturity 30 to 59 Days [Member] | Mortgage servicing rights    
Assets Sold under Agreements to Repurchase [Line Items]    
Repurchase agreements 0 0
Maturity 60 to 89 Days [Member]    
Assets Sold under Agreements to Repurchase [Line Items]    
Repurchase agreements 2,062,234 6,687,285
Maturity 60 to 89 Days [Member] | US Government Agencies Debt Securities [Member]    
Assets Sold under Agreements to Repurchase [Line Items]    
Repurchase agreements 2,060,087 6,355,887
Maturity 60 to 89 Days [Member] | Mortgage-backed Securities, Issued by Private Enterprises [Member]    
Assets Sold under Agreements to Repurchase [Line Items]    
Repurchase agreements 628 329,493
Maturity 60 to 89 Days [Member] | Inverse Interest-Only Securities [Member]    
Assets Sold under Agreements to Repurchase [Line Items]    
Repurchase agreements 1,519 1,905
Maturity 60 to 89 Days [Member] | Mortgage servicing rights    
Assets Sold under Agreements to Repurchase [Line Items]    
Repurchase agreements 0 0
Maturity 90 to 119 Days [Member]    
Assets Sold under Agreements to Repurchase [Line Items]    
Repurchase agreements 1,610,198 4,740,217
Maturity 90 to 119 Days [Member] | US Government Agencies Debt Securities [Member]    
Assets Sold under Agreements to Repurchase [Line Items]    
Repurchase agreements 1,598,052 4,227,589
Maturity 90 to 119 Days [Member] | Mortgage-backed Securities, Issued by Private Enterprises [Member]    
Assets Sold under Agreements to Repurchase [Line Items]    
Repurchase agreements 0 489,352
Maturity 90 to 119 Days [Member] | Inverse Interest-Only Securities [Member]    
Assets Sold under Agreements to Repurchase [Line Items]    
Repurchase agreements 12,146 23,276
Maturity 90 to 119 Days [Member] | Mortgage servicing rights    
Assets Sold under Agreements to Repurchase [Line Items]    
Repurchase agreements 0 0
Maturity 120 to 364 days [Member]    
Assets Sold under Agreements to Repurchase [Line Items]    
Repurchase agreements 1,808,099 6,113,673
Maturity 120 to 364 days [Member] | US Government Agencies Debt Securities [Member]    
Assets Sold under Agreements to Repurchase [Line Items]    
Repurchase agreements 1,808,099 5,532,219
Maturity 120 to 364 days [Member] | Mortgage-backed Securities, Issued by Private Enterprises [Member]    
Assets Sold under Agreements to Repurchase [Line Items]    
Repurchase agreements 0 306,529
Maturity 120 to 364 days [Member] | Inverse Interest-Only Securities [Member]    
Assets Sold under Agreements to Repurchase [Line Items]    
Repurchase agreements 0 12,310
Maturity 120 to 364 days [Member] | Mortgage servicing rights    
Assets Sold under Agreements to Repurchase [Line Items]    
Repurchase agreements $ 0 $ 262,615