Revenue Recognition (Customer Accounts Receivable) (Details) - USD ($) $ in Millions |
Sep. 30, 2026 |
Dec. 31, 2025 |
|---|---|---|
| Revenue from Contract with Customer [Abstract] | ||
| Customer Accounts Receivable, Billed (Less Reserve) | $ 623.8 | $ 698.8 |
| Customer Accounts Receivable, Unbilled (Less Reserve) | $ 123.0 | $ 465.2 |