Service Revenue (Summary of Changes in Deferred Costs to Obtain and Fulfill Contracts) (Details) - USD ($) $ in Millions |
12 Months Ended | ||
|---|---|---|---|
May 31, 2026 |
May 31, 2025 |
May 31, 2024 |
|
| Capitalized Contract Cost [Line Items] | |||
| Amortization | $ 249.2 | $ 236.5 | $ 231.7 |
| Costs To Fulfill Contracts [Member] | |||
| Capitalized Contract Cost [Line Items] | |||
| Balance, beginning of period | 87.0 | 76.6 | |
| Capitalization of costs | 83.0 | 37.8 | |
| Amortization | (34.1) | (27.4) | |
| Balance, end of period | 135.9 | 87.0 | 76.6 |
| Costs To Obtain Contracts [Member] | |||
| Capitalized Contract Cost [Line Items] | |||
| Balance, beginning of period | 609.0 | 609.4 | |
| Capitalization of costs | 259.5 | 208.7 | |
| Amortization | (215.1) | (209.1) | |
| Balance, end of period | $ 653.4 | $ 609.0 | $ 609.4 |