Revenue Recognition (Customer Accounts Receivable) (Details) - USD ($) $ in Millions |
Sep. 30, 2024 |
Dec. 31, 2023 |
|---|---|---|
| Revenue from Contract with Customer [Abstract] | ||
| Customer Accounts Receivable, Billed (Less Reserve) | $ 350.4 | $ 479.4 |
| Customer Accounts Receivable, Unbilled (Less Reserve) | $ 198.8 | $ 337.6 |