| Financial Assets and Liabilities, Measured at Fair Value Recurring Basis [Table Text Block] |
The following table presents a summary of fair value measurements by level and carrying values for items measured at fair value on a recurring basis in the Consolidated Balance Sheets: | | | | | | | | | | | | | | | | | | | | | | | | | | | | (in millions) | | Quoted Prices
in Active
Markets
(Level 1) | | Other
Observable
Inputs
(Level 2) | | Unobservable
Inputs
(Level 3) | | Total
Fair and Carrying
Value | | December 31, 2025 | | | | | | | | | | Cash and cash equivalents | | $ | 19,848 | | | $ | 4,517 | | | $ | — | | | $ | 24,365 | | | Debt securities - available-for-sale: | | | | | | | | | | U.S. government and agency obligations | | 3,778 | | | 154 | | | — | | | 3,932 | | | State and municipal obligations | | — | | | 6,325 | | | — | | | 6,325 | | | Corporate obligations | | — | | | 25,123 | | | 423 | | | 25,546 | | | U.S. agency mortgage-backed securities | | — | | | 9,719 | | | — | | | 9,719 | | | Non-U.S. agency mortgage-backed securities | | — | | | 2,660 | | | — | | | 2,660 | | | Total debt securities - available-for-sale | | 3,778 | | | 43,981 | | | 423 | | | 48,182 | | | Equity securities | | 2,083 | | | 20 | | | 67 | | | 2,170 | | | Loan receivables | | — | | | — | | | 882 | | | 882 | | | Total assets at fair value | | $ | 25,709 | | | $ | 48,518 | | | $ | 1,372 | | | $ | 75,599 | | | Percentage of total assets at fair value | | 34 | % | | 64 | % | | 2 | % | | 100 | % | | December 31, 2024 | | | | | | | | | | Cash and cash equivalents | | $ | 25,248 | | | $ | 64 | | | $ | — | | | $ | 25,312 | | | Debt securities - available-for-sale: | | | | | | | | | | U.S. government and agency obligations | | 4,194 | | | 133 | | | — | | | 4,327 | | | State and municipal obligations | | — | | | 6,984 | | | — | | | 6,984 | | | Corporate obligations | | 29 | | | 22,841 | | | 437 | | | 23,307 | | | U.S. agency mortgage-backed securities | | — | | | 9,584 | | | — | | | 9,584 | | | Non-U.S. agency mortgage-backed securities | | — | | | 2,717 | | | — | | | 2,717 | | | Total debt securities - available-for-sale | | 4,223 | | | 42,259 | | | 437 | | | 46,919 | | | Equity securities | | 1,859 | | | 24 | | | 65 | | | 1,948 | | | Loan receivables | | — | | | — | | | 293 | | | 293 | | | Total assets at fair value | | $ | 31,330 | | | $ | 42,347 | | | $ | 795 | | | $ | 74,472 | | | Percentage of total assets at fair value | | 42 | % | | 57 | % | | 1 | % | | 100 | % |
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| Fair Value Measurements, Nonrecurring [Table Text Block] |
The following table presents a summary of fair value measurements by level and carrying values for certain financial instruments not measured at fair value on a recurring basis in the Consolidated Balance Sheets: | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | (in millions) | | Quoted Prices
in Active
Markets
(Level 1) | | Other
Observable
Inputs
(Level 2) | | Unobservable
Inputs
(Level 3) | | Total
Fair
Value | | Total Carrying Value | | December 31, 2025 | | | | | | | | | | | | Debt securities - held-to-maturity | | $ | 463 | | | $ | 26 | | | $ | — | | | $ | 489 | | | $ | 490 | | | Loan receivables | | — | | | 1,700 | | | 6,923 | | | 8,623 | | | 8,860 | | | Long-term debt and other financing obligations | | — | | | 72,143 | | | — | | | 72,143 | | | 76,140 | | | December 31, 2024 | | | | | | | | | | | | Debt securities - held-to-maturity | | $ | 482 | | | $ | 26 | | | $ | — | | | $ | 508 | | | $ | 512 | | | Loan receivables | | — | | | 1,413 | | | 5,101 | | | 6,514 | | | 6,876 | | | Long-term debt and other financing obligations | | — | | | 70,565 | | | — | | | 70,565 | | | 75,604 | |
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