v3.26.1
Investments (Short-Term and Long-Term Investments) (Details) - USD ($)
$ in Millions
Mar. 31, 2026
Dec. 31, 2025
Schedule of Investments [Line Items]    
Debt Securities, Available-for-sale, Amortized Cost $ 51,867 $ 49,578
Securities, Available for sale Debt Securities, Gross Unrealized Gains 116 229
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax (1,877) (1,625)
Debt Securities, Available-for-sale 50,106 48,182
Held-to-maturity securities, Amortized Cost 474 490
Securities, Held to maturity, Unrecognized Holding Gain 1 2
Debt Securities, Held-to-maturity, Accumulated Unrecognized Loss (4) (3)
Debt Securities, Held-to-maturity, Fair Value 471 489
Debt Securities, Available-for-Sale and Held-to-Maturity, Fair Value 50,577 48,671
Debt Securities, Available-for-Sale and Held-to-Maturity, Cumulative Unrecognized Loss (1,881) (1,628)
Debt Securities, Available-for-Sale and Held-to-Maturity, Cumulative Unrecognized Gain 117 231
Debt Securities, Available-for-Sale and Held-to-Maturity, Amortized Cost 52,341 50,068
Debt Securities [Member]    
Schedule of Investments [Line Items]    
Debt Securities, Available-for-sale 50,106 48,182
U.S. Government and Agency Obligations [Member]    
Schedule of Investments [Line Items]    
Debt Securities, Available-for-sale, Amortized Cost 3,605 4,086
Securities, Available for sale Debt Securities, Gross Unrealized Gains 0 2
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax (168) (156)
Debt Securities, Available-for-sale 3,437 3,932
Held-to-maturity securities, Amortized Cost 445 461
Securities, Held to maturity, Unrecognized Holding Gain 1 2
Debt Securities, Held-to-maturity, Accumulated Unrecognized Loss (1) (1)
Debt Securities, Held-to-maturity, Fair Value 445 462
State and Municipal Obligations [Member]    
Schedule of Investments [Line Items]    
Debt Securities, Available-for-sale, Amortized Cost 6,027 6,533
Securities, Available for sale Debt Securities, Gross Unrealized Gains 14 24
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax (262) (232)
Debt Securities, Available-for-sale 5,779 6,325
Held-to-maturity securities, Amortized Cost 26 26
Securities, Held to maturity, Unrecognized Holding Gain 0 0
Debt Securities, Held-to-maturity, Accumulated Unrecognized Loss (3) (2)
Debt Securities, Held-to-maturity, Fair Value 23 24
Corporate Obligations [Member]    
Schedule of Investments [Line Items]    
Debt Securities, Available-for-sale, Amortized Cost 28,157 25,927
Securities, Available for sale Debt Securities, Gross Unrealized Gains 80 159
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax (699) (540)
Debt Securities, Available-for-sale 27,538 25,546
Held-to-maturity securities, Amortized Cost 3 3
Securities, Held to maturity, Unrecognized Holding Gain 0 0
Debt Securities, Held-to-maturity, Accumulated Unrecognized Loss 0 0
Debt Securities, Held-to-maturity, Fair Value 3 3
U.S. Agency Mortgage-Backed Securities [Member]    
Schedule of Investments [Line Items]    
Debt Securities, Available-for-sale, Amortized Cost 10,901 10,284
Securities, Available for sale Debt Securities, Gross Unrealized Gains 17 33
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax (643) (598)
Debt Securities, Available-for-sale 10,275 9,719
Non-U.S. Agency Mortgage-Backed Securities [Member]    
Schedule of Investments [Line Items]    
Debt Securities, Available-for-sale, Amortized Cost 3,177 2,748
Securities, Available for sale Debt Securities, Gross Unrealized Gains 5 11
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax (105) (99)
Debt Securities, Available-for-sale $ 3,077 $ 2,660