v3.26.1
Investments (HTM Major Security Types) (Details) - USD ($)
$ in Millions
Jun. 30, 2026
Dec. 31, 2025
Schedule of Held-to-maturity Securities [Line Items]    
Debt Securities, Held-to-maturity, Accumulated Unrecognized Gain $ 7 $ 9
Debt Securities, Held-to-maturity, Accumulated Unrecognized Loss (5) (4)
Held-to-Maturity Securities, Fair Value 415 452
Debt Securities, Held-to-Maturity, Excluding Accrued Interest, after Allowance for Credit Loss 413 447
Debt Securities, Held-to-Maturity, Accrued Interest, after Allowance for Credit Loss 2 2
US Government-sponsored Enterprises Debt Securities [Member]    
Schedule of Held-to-maturity Securities [Line Items]    
Debt Securities, Held-to-maturity, Accumulated Unrecognized Gain 7 8
Debt Securities, Held-to-maturity, Accumulated Unrecognized Loss (1) 0
Held-to-Maturity Securities, Fair Value 130 132
Debt Securities, Held-to-Maturity, Excluding Accrued Interest, after Allowance for Credit Loss 124 124
State or local housing agency obligations [Member]    
Schedule of Held-to-maturity Securities [Line Items]    
Debt Securities, Held-to-maturity, Accumulated Unrecognized Gain 0 1
Debt Securities, Held-to-maturity, Accumulated Unrecognized Loss 0 0
Held-to-Maturity Securities, Fair Value 17 22
Debt Securities, Held-to-Maturity, Excluding Accrued Interest, after Allowance for Credit Loss 17 21
Non-mortgage-backed securities [Member]    
Schedule of Held-to-maturity Securities [Line Items]    
Debt Securities, Held-to-maturity, Accumulated Unrecognized Gain 7 9
Debt Securities, Held-to-maturity, Accumulated Unrecognized Loss (1) 0
Held-to-Maturity Securities, Fair Value 147 154
Debt Securities, Held-to-Maturity, Excluding Accrued Interest, after Allowance for Credit Loss 141 145
Mortgage-backed Securities, Issued by Private Enterprises [Member]    
Schedule of Held-to-maturity Securities [Line Items]    
Debt Securities, Held-to-maturity, Accumulated Unrecognized Gain 0 0
Debt Securities, Held-to-maturity, Accumulated Unrecognized Loss 0 0
Held-to-Maturity Securities, Fair Value 2 2
Debt Securities, Held-to-Maturity, Excluding Accrued Interest, after Allowance for Credit Loss 2 2
Mortgage-backed securities [Member]    
Schedule of Held-to-maturity Securities [Line Items]    
Debt Securities, Held-to-maturity, Accumulated Unrecognized Gain 0 0
Debt Securities, Held-to-maturity, Accumulated Unrecognized Loss (4) (4)
Held-to-Maturity Securities, Fair Value 268 298
Debt Securities, Held-to-Maturity, Excluding Accrued Interest, after Allowance for Credit Loss 272 302
Single Family [Member] | U.S. obligations MBS [Member]    
Schedule of Held-to-maturity Securities [Line Items]    
Debt Securities, Held-to-maturity, Accumulated Unrecognized Gain 0 0
Debt Securities, Held-to-maturity, Accumulated Unrecognized Loss 0 0
Held-to-Maturity Securities, Fair Value 1 1
Debt Securities, Held-to-Maturity, Excluding Accrued Interest, after Allowance for Credit Loss 1 1
Single Family [Member] | Mortgage-backed securities, GSE [Member]    
Schedule of Held-to-maturity Securities [Line Items]    
Debt Securities, Held-to-maturity, Accumulated Unrecognized Gain 0 0
Debt Securities, Held-to-maturity, Accumulated Unrecognized Loss (4) (4)
Held-to-Maturity Securities, Fair Value 265 295
Debt Securities, Held-to-Maturity, Excluding Accrued Interest, after Allowance for Credit Loss $ 269 $ 299