v3.26.1
Fair Value Measurements (Fair Value Option, Fair Value and Unpaid Principal Balance) (Details) - Mortgage loans held for sale [Member] - USD ($)
$ in Millions
Mar. 31, 2026
Dec. 31, 2025
Fair Value, Option, Quantitative Disclosures [Line Items]    
Loans Held for Sale $ 328 $ 266
Fair Value Option Mortgages Held For Sale Aggregate Unpaid Principal $ 325 $ 259