v3.26.1
Pledged Assets (Assets Pledged as Collateral) (Details) - USD ($)
$ in Millions
Jun. 30, 2026
Dec. 31, 2025
Jun. 30, 2025
Offsetting Assets and Liabilities [Line Items]      
Accrued interest on pledged securities $ 503 $ 434  
Restricted cash 1,329 1,292 $ 1,216
Total Fair Value of Securities Pledged and Accrued Interest 94,631    
Total Fair Value Of Agency Securities Pledged And Accrued Interest   89,786  
Security Owned and Pledged as Collateral, Fair Value 92,210 87,420  
Retained Interests in Consolidated VIE's Pledged as Collateral Under Repurchase Agreements   30  
Repurchase Agreements [Member]      
Offsetting Assets and Liabilities [Line Items]      
Security Owned and Pledged as Collateral, Fair Value 80,952 74,213  
Derivative Agreements and Other      
Offsetting Assets and Liabilities [Line Items]      
Total Fair Value of Securities Pledged and Accrued Interest 1,889 1,807  
Security Owned and Pledged as Collateral, Fair Value 10 115  
Repurchase Agreements [Member]      
Offsetting Assets and Liabilities [Line Items]      
Accrued interest on pledged securities 496 430  
Total Fair Value of Securities Pledged and Accrued Interest 92,742    
Total Fair Value Of Agency Securities Pledged And Accrued Interest   87,894  
Variable Interest Entity, Primary Beneficiary [Member]      
Offsetting Assets and Liabilities [Line Items]      
Accrued interest on pledged securities 0 0  
Total Fair Value of Securities Pledged and Accrued Interest 0    
Total Fair Value Of Agency Securities Pledged And Accrued Interest   85  
Security Owned and Pledged as Collateral, Fair Value 0 85  
Includes Sold But Not Yet Settled Securities [Member]      
Offsetting Assets and Liabilities [Line Items]      
Security Owned and Pledged as Collateral, Fair Value 80,962 74,413  
Credit Risk Transfer Securities [Member]      
Offsetting Assets and Liabilities [Line Items]      
Security Owned and Pledged as Collateral, Fair Value 525 558  
Credit Risk Transfer Securities [Member] | Repurchase Agreements [Member]      
Offsetting Assets and Liabilities [Line Items]      
Security Owned and Pledged as Collateral, Fair Value 525 558  
Non-Agency [Member]      
Offsetting Assets and Liabilities [Line Items]      
Security Owned and Pledged as Collateral, Fair Value 8 13  
Non-Agency [Member] | Repurchase Agreements [Member]      
Offsetting Assets and Liabilities [Line Items]      
Security Owned and Pledged as Collateral, Fair Value 8 13  
US Treasury Securities [Member]      
Offsetting Assets and Liabilities [Line Items]      
Security Owned and Pledged as Collateral, Fair Value 11,304 13,076  
US Treasury Securities [Member] | Repurchase Agreements [Member]      
Offsetting Assets and Liabilities [Line Items]      
Security Owned and Pledged as Collateral, Fair Value 10,725 12,636  
US Treasury Securities [Member] | Derivative Agreements and Other      
Offsetting Assets and Liabilities [Line Items]      
Security Owned and Pledged as Collateral, Fair Value 579 440  
Derivative Agreements and Other      
Offsetting Assets and Liabilities [Line Items]      
Accrued interest on pledged securities 7 4  
Repurchase Agreements [Member]      
Offsetting Assets and Liabilities [Line Items]      
Restricted cash 36 44  
Excluding Cash Received [Member]      
Offsetting Assets and Liabilities [Line Items]      
Restricted cash 1,329 1,292  
Derivative Agreements and Other      
Offsetting Assets and Liabilities [Line Items]      
Restricted cash $ 1,293 $ 1,248