v3.26.1
Investments (Short-Term and Long-Term Investments) (Details) - USD ($)
$ in Millions
Jun. 30, 2026
Dec. 31, 2025
Schedule of Investments [Line Items]    
Debt Securities, Available-for-sale, Amortized Cost $ 52,069 $ 49,578
Securities, Available for sale Debt Securities, Gross Unrealized Gains 109 229
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax (1,893) (1,625)
Debt Securities, Available-for-sale 50,285 48,182
Held-to-maturity securities, Amortized Cost 476 490
Securities, Held to maturity, Unrecognized Holding Gain 0 2
Debt Securities, Held-to-maturity, Accumulated Unrecognized Loss (4) (3)
Debt Securities, Held-to-maturity, Fair Value 472 489
Debt Securities, Available-for-Sale and Held-to-Maturity, Fair Value 50,757 48,671
Debt Securities, Available-for-Sale and Held-to-Maturity, Cumulative Unrecognized Loss (1,897) (1,628)
Debt Securities, Available-for-Sale and Held-to-Maturity, Cumulative Unrecognized Gain 109 231
Debt Securities, Available-for-Sale and Held-to-Maturity, Amortized Cost 52,545 50,068
Debt Securities [Member]    
Schedule of Investments [Line Items]    
Debt Securities, Available-for-sale 50,285 48,182
U.S. Government and Agency Obligations [Member]    
Schedule of Investments [Line Items]    
Debt Securities, Available-for-sale, Amortized Cost 3,227 4,086
Securities, Available for sale Debt Securities, Gross Unrealized Gains 0 2
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax (180) (156)
Debt Securities, Available-for-sale 3,047 3,932
Held-to-maturity securities, Amortized Cost 448 461
Securities, Held to maturity, Unrecognized Holding Gain 0 2
Debt Securities, Held-to-maturity, Accumulated Unrecognized Loss (2) (1)
Debt Securities, Held-to-maturity, Fair Value 446 462
State and Municipal Obligations [Member]    
Schedule of Investments [Line Items]    
Debt Securities, Available-for-sale, Amortized Cost 5,752 6,533
Securities, Available for sale Debt Securities, Gross Unrealized Gains 20 24
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax (221) (232)
Debt Securities, Available-for-sale 5,551 6,325
Held-to-maturity securities, Amortized Cost 25 26
Securities, Held to maturity, Unrecognized Holding Gain 0 0
Debt Securities, Held-to-maturity, Accumulated Unrecognized Loss (2) (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 28,892 25,927
Securities, Available for sale Debt Securities, Gross Unrealized Gains 72 159
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax (703) (540)
Debt Securities, Available-for-sale 28,261 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 10,939 10,284
Securities, Available for sale Debt Securities, Gross Unrealized Gains 13 33
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax (684) (598)
Debt Securities, Available-for-sale 10,268 9,719
Non-U.S. Agency Mortgage-Backed Securities [Member]    
Schedule of Investments [Line Items]    
Debt Securities, Available-for-sale, Amortized Cost 3,259 2,748
Securities, Available for sale Debt Securities, Gross Unrealized Gains 4 11
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax (105) (99)
Debt Securities, Available-for-sale $ 3,158 $ 2,660