v3.25.2
Investments (Amortized Cost and Fair Value of Available-for-Sale Debt Securities by Contractual Maturity) (Details) - USD ($)
$ in Millions
Jun. 30, 2025
Dec. 31, 2024
Schedule of Investments [Line Items]    
Due in one year or less, Amortized Cost $ 3,530  
Due after one year through five years, Amortized Cost 14,415  
Due after five years through ten years, Amortized Cost 11,983  
Due after ten years, Amortized Cost 5,539  
Total debt securities - available-for-sale, Amortized Cost 48,683 $ 49,815
Due in one year or less, Fair Value 3,506  
Due after one year through five years, Fair Value 14,106  
Due after five years through ten years, Fair Value 11,485  
Due after ten years, Fair Value 5,190  
Debt Securities, Available-for-sale 46,608 46,919
Debt Securities, Held-to-Maturity, Amortized Cost, Maturity, Allocated and Single Maturity Date, Year One 319  
Debt Securities, Held-to-Maturity, Amortized Cost, Maturity, Allocated and Single Maturity Date, after Year One Through Five 152  
Debt Securities, Held-to-Maturity, Amortized Cost, Maturity, Allocated and Single Maturity Date, after Year 5 Through 10 5  
Debt Securities, Held-to-Maturity, Amortized Cost, Maturity, Allocated and Single Maturity Date, after Year 10 17  
Debt Securities, Held-to-maturity 493 512
Held-to-maturity Securities, Debt Maturities, within One Year, Fair Value 319  
Debt Securities, Held-to-Maturity, Fair Value, Maturity, Allocated and Single Maturity Date, after Year One Through Five 152  
Debt Securities, Held-to-Maturity, Fair Value, Maturity, Allocated and Single Maturity Date, after Year 5 Through 10 5  
Debt Securities, Held-to-Maturity, Fair Value, Maturity, Allocated and Single Maturity Date, after Year 10 14  
Debt Securities, Held-to-maturity, Fair Value 490 508
U.S. Agency Mortgage-Backed Securities [Member]    
Schedule of Investments [Line Items]    
Mortgage-backed securities, Amortized Cost 10,341  
Total debt securities - available-for-sale, Amortized Cost 10,341 10,577
Mortgage-backed securities, Fair Value 9,566  
Debt Securities, Available-for-sale 9,566 9,584
Non-U.S. Agency Mortgage-Backed Securities [Member]    
Schedule of Investments [Line Items]    
Mortgage-backed securities, Amortized Cost 2,875  
Total debt securities - available-for-sale, Amortized Cost 2,875 2,890
Mortgage-backed securities, Fair Value 2,755  
Debt Securities, Available-for-sale $ 2,755 $ 2,717