v3.26.1
Investments (Amortized Cost and Fair Value of Available-for-Sale Debt Securities by Contractual Maturity) (Details) - USD ($)
$ in Millions
Jun. 30, 2026
Dec. 31, 2025
Schedule of Investments [Line Items]    
Due in one year or less, Amortized Cost $ 2,957  
Due after one year through five years, Amortized Cost 14,192  
Due after five years through ten years, Amortized Cost 12,802  
Due after ten years, Amortized Cost 7,920  
Total debt securities - available-for-sale, Amortized Cost 52,069 $ 49,578
Due in one year or less, Fair Value 2,942  
Due after one year through five years, Fair Value 13,816  
Due after five years through ten years, Fair Value 12,408  
Due after ten years, Fair Value 7,693  
Debt Securities, Available-for-sale 50,285 48,182
Debt Securities, Held-to-Maturity, Amortized Cost, Maturity, Allocated and Single Maturity Date, Year One 280  
Debt Securities, Held-to-Maturity, Amortized Cost, Maturity, Allocated and Single Maturity Date, after Year One Through Five 175  
Debt Securities, Held-to-Maturity, Amortized Cost, Maturity, Allocated and Single Maturity Date, after Year 5 Through 10 4  
Debt Securities, Held-to-Maturity, Amortized Cost, Maturity, Allocated and Single Maturity Date, after Year 10 17  
Debt Securities, Held-to-maturity 476 490
Held-to-maturity Securities, Debt Maturities, within One Year, Fair Value 280  
Debt Securities, Held-to-Maturity, Fair Value, Maturity, Allocated and Single Maturity Date, after Year One Through Five 173  
Debt Securities, Held-to-Maturity, Fair Value, Maturity, Allocated and Single Maturity Date, after Year 5 Through 10 4  
Debt Securities, Held-to-Maturity, Fair Value, Maturity, Allocated and Single Maturity Date, after Year 10 15  
Debt Securities, Held-to-maturity, Fair Value 472 489
U.S. Agency Mortgage-Backed Securities [Member]    
Schedule of Investments [Line Items]    
Mortgage-backed securities, Amortized Cost 10,939  
Total debt securities - available-for-sale, Amortized Cost 10,939 10,284
Mortgage-backed securities, Fair Value 10,268  
Debt Securities, Available-for-sale 10,268 9,719
Non-U.S. Agency Mortgage-Backed Securities [Member]    
Schedule of Investments [Line Items]    
Mortgage-backed securities, Amortized Cost 3,259  
Total debt securities - available-for-sale, Amortized Cost 3,259 2,748
Mortgage-backed securities, Fair Value 3,158  
Debt Securities, Available-for-sale $ 3,158 $ 2,660