v3.26.1
Available -for-sale Securities (Available-for-sale by Major Security Type) (Details) - USD ($)
$ in Millions
Jun. 30, 2026
Dec. 31, 2025
Debt Securities, Available-for-sale [Line Items]    
Gross unrealized gains on available-for-sale securities $ 39 $ 27
Gross unrealized loss on available-for-sale securities (10) (2)
Available-for-Sale, Estimated Fair Value 13,816 8,933
Available-for-Sale, Accrued Interest Receivable   57
Available-for-sale securities, amortized cost [1] 13,787 8,908
US Treasury Securities [Member]    
Debt Securities, Available-for-sale [Line Items]    
Gross unrealized gains on available-for-sale securities 11 13
Gross unrealized loss on available-for-sale securities 0 0
Available-for-Sale, Estimated Fair Value 6,045 5,594
Available-for-sale securities, amortized cost [1] 6,034 5,581
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]    
Debt Securities, Available-for-sale [Line Items]    
Gross unrealized gains on available-for-sale securities 28 14
Gross unrealized loss on available-for-sale securities (10) (2)
Available-for-Sale, Estimated Fair Value [2] 7,771 3,339
Available-for-sale securities, amortized cost [1],[2] $ 7,753 $ 3,327
[1] Amortized cost includes adjustments made to the cost basis for accretion, amortization, fair value hedge accounting adjustments, and excludes accrued interest receivable of $78 and $57 as of June 30, 2026 and December 31, 2025, respectively.
[2] Mortgage-backed securities (MBS) are not presented by contractual maturity because their actual maturities may differ from contractual maturities as borrowers may have the right to call or prepay obligations with or without call or prepayment fees.