Stock Plans: (Assumptions Used to Determine the Grant Date Fair Value of the Performance Share Unit Awards Subject to the TSR Performance Metric) (Details) - Performance Shares |
6 Months Ended | |
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Jun. 30, 2026 |
Jun. 30, 2025 |
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| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | ||
| Average risk-free interest rate | 3.50% | 4.10% |
| Average expected volatility | 21.70% | 21.00% |
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- Definition The estimated measure of the percentage by which a share price is expected to fluctuate during a period. Volatility also may be defined as a probability-weighted measure of the dispersion of returns about the mean. The volatility of a share price is the standard deviation of the continuously compounded rates of return on the share over a specified period. That is the same as the standard deviation of the differences in the natural logarithms of the stock prices plus dividends, if any, over the period. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition The risk-free interest rate assumption that is used in valuing an option on its own shares. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Details
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