| | 2020-12-31 | 2021-12-31 | 2022-12-31 | 2023-12-31 | 2024-12-31 | 2025-06-30 | 2025-09-30 |
| Amortization Of Securities | | 1668000000.0 | 1824000000.0 | 2044000000.0 | 2282000000.0 | 2408000000.0 | 2462000000.0 |
| Beginning Cash Position | | 239000000.0 | 337000000.0 | 344000000.0 | 189000000.0 | 210000000.0 | 281000000.0 |
| Capital Expenditure | | -133000000.0 | -175000000.0 | -215000000.0 | -145000000.0 | -112000000.0 | -97000000.0 |
| Cash Dividends Paid | | -506000000.0 | -527000000.0 | -549000000.0 | -577000000.0 | -595000000.0 | -604000000.0 |
| Cash Flow From Continuing Financing Activities | | -1581000000.0 | -2710000000.0 | -1947000000.0 | -2076000000.0 | -2218000000.0 | -2242000000.0 |
| Cash Flow From Continuing Investing Activities | | -2466000000.0 | -1277000000.0 | -2431000000.0 | -3768000000.0 | -3589000000.0 | -3815000000.0 |
| Cash Flow From Continuing Operating Activities | | 4093000000.0 | 4008000000.0 | 4220000000.0 | 5909000000.0 | 5828000000.0 | 5988000000.0 |
| Cash Flow From Discontinued Operation | -58000000.0 | 58000000.0 | 0.0 | | | | |
| Change In Other Working Capital | | 109000000.0 | -226000000.0 | -36000000.0 | -368000000.0 | -471000000.0 | -438000000.0 |
| Change In Receivables | | -773000000.0 | -1032000000.0 | -863000000.0 | -512000000.0 | -508000000.0 | -543000000.0 |
| Change In Working Capital | | 1747000000.0 | 934000000.0 | 920000000.0 | 2178000000.0 | 1956000000.0 | 1863000000.0 |
| Changes In Account Receivables | | -773000000.0 | -1032000000.0 | -863000000.0 | -512000000.0 | -508000000.0 | -543000000.0 |
| Changes In Cash | | 46000000.0 | 21000000.0 | -158000000.0 | 65000000.0 | 21000000.0 | -69000000.0 |
| Common Stock Dividend Paid | | -485000000.0 | -506000000.0 | -528000000.0 | -556000000.0 | -574000000.0 | -583000000.0 |
| Common Stock Payments | | -1702000000.0 | -1550000000.0 | -1400000000.0 | -1514000000.0 | -1629000000.0 | -1629000000.0 |
| Depreciation And Amortization | | 680000000.0 | 625000000.0 | 510000000.0 | 356000000.0 | 355000000.0 | 345000000.0 |
| Effect Of Exchange Rate Changes | | -6000000.0 | -14000000.0 | 3000000.0 | -20000000.0 | -12000000.0 | -6000000.0 |
| End Cash Position | | 337000000.0 | 344000000.0 | 189000000.0 | 234000000.0 | 231000000.0 | 212000000.0 |
| Financing Cash Flow | | -1581000000.0 | -2710000000.0 | -1947000000.0 | -2076000000.0 | -2218000000.0 | -2242000000.0 |
| Free Cash Flow | | 3960000000.0 | 3833000000.0 | 4005000000.0 | 5764000000.0 | 5716000000.0 | 5891000000.0 |
| Gain Loss On Investment Securities | | -530000000.0 | 627000000.0 | 188000000.0 | 61000000.0 | 45000000.0 | 38000000.0 |
| Gain Loss On Sale Of Business | 48000000.0 | 21000000.0 | 0.0 | 0.0 | | | |
| Income Tax Paid Supplemental Data | | 496000000.0 | 548000000.0 | 622000000.0 | 812000000.0 | 879000000.0 | 776000000.0 |
| Interest Paid Supplemental Data | | 214000000.0 | 212000000.0 | 209000000.0 | 211000000.0 | 208000000.0 | 207000000.0 |
| Investing Cash Flow | | -2466000000.0 | -1277000000.0 | -2431000000.0 | -3768000000.0 | -3589000000.0 | -3815000000.0 |
| Issuance Of Capital Stock | 0.0 | | | | | | |
| Issuance Of Debt | 0.0 | 588000000.0 | 0.0 | 0.0 | | | |
| Long Term Debt Issuance | 0.0 | 588000000.0 | 0.0 | 0.0 | | | |
| Long Term Debt Payments | | 0.0 | -600000000.0 | 0.0 | 0.0 | | |
| Net Business Purchase And Sale | | -769000000.0 | -746000000.0 | -671000000.0 | -426000000.0 | -543000000.0 | -618000000.0 |
| Net Common Stock Issuance | | -1702000000.0 | -1550000000.0 | -1400000000.0 | -1514000000.0 | -1629000000.0 | -1629000000.0 |
| Net Income From Continuing Operations | | 2371000000.0 | 1819000000.0 | 2504000000.0 | 3111000000.0 | 3245000000.0 | 3558000000.0 |
| Net Investment Purchase And Sale | | -675000000.0 | 263000000.0 | -1505000000.0 | -2905000000.0 | -2786000000.0 | -2873000000.0 |
| Net Issuance Payments Of Debt | | 588000000.0 | -600000000.0 | 0.0 | 0.0 | | |
| Net Long Term Debt Issuance | -500000000.0 | 588000000.0 | -600000000.0 | | | | |
| Net Other Financing Charges | | 14000000.0 | -14000000.0 | -4000000.0 | -7000000.0 | 8000000.0 | 7000000.0 |
| Net Other Investing Changes | | -9000000.0 | 4000000.0 | -21000000.0 | -7000000.0 | -61000000.0 | -43000000.0 |
| Net PPEPurchase And Sale | | -133000000.0 | -175000000.0 | -215000000.0 | -145000000.0 | -112000000.0 | -97000000.0 |
| Net Preferred Stock Issuance | 0.0 | | | | | | |
| Operating Cash Flow | | 4093000000.0 | 4008000000.0 | 4220000000.0 | 5909000000.0 | 5828000000.0 | 5988000000.0 |
| Operating Gains Losses | | -509000000.0 | 627000000.0 | 188000000.0 | 61000000.0 | 45000000.0 | 38000000.0 |
| Other Cash Adjustment Outside Changein Cash | -58000000.0 | 58000000.0 | 0.0 | 0.0 | | | |
| Other Non Cash Items | | -1864000000.0 | -1821000000.0 | -1946000000.0 | -2079000000.0 | -2225000000.0 | -2328000000.0 |
| Preferred Stock Dividend Paid | | -21000000.0 | -21000000.0 | -21000000.0 | -21000000.0 | -21000000.0 | -21000000.0 |
| Preferred Stock Issuance | 0.0 | | | | | | |
| Proceeds From Stock Option Exercised | | 25000000.0 | -19000000.0 | 6000000.0 | 22000000.0 | -2000000.0 | -16000000.0 |
| Purchase Of Business | | -1317000000.0 | -1095000000.0 | -966000000.0 | -664000000.0 | -795000000.0 | -887000000.0 |
| Purchase Of Investment | | -23758000000.0 | -16002000000.0 | -10486000000.0 | -14199000000.0 | -13828000000.0 | -13666000000.0 |
| Purchase Of PPE | | -133000000.0 | -175000000.0 | -215000000.0 | -145000000.0 | -112000000.0 | -97000000.0 |
| Repayment Of Debt | | 0.0 | -600000000.0 | 0.0 | 0.0 | | |
| Repurchase Of Capital Stock | | -1702000000.0 | -1550000000.0 | -1400000000.0 | -1514000000.0 | -1629000000.0 | -1629000000.0 |
| Sale Of Business | | 548000000.0 | 349000000.0 | 295000000.0 | 238000000.0 | 252000000.0 | 269000000.0 |
| Sale Of Investment | | 23083000000.0 | 16265000000.0 | 8981000000.0 | 11294000000.0 | 11042000000.0 | 10793000000.0 |