Annual report pursuant to Section 13 and 15(d)

Service Revenue (Summary of Changes in Deferred Costs to Obtain and Fulfill Contracts) (Details)

v3.20.2
Service Revenue (Summary of Changes in Deferred Costs to Obtain and Fulfill Contracts) (Details) - USD ($)
$ in Millions
12 Months Ended
May 31, 2020
May 31, 2019
May 31, 2018
Capitalized Contract Cost [Line Items]      
Amortization $ 186.1 $ 180.2 $ 174.7
Costs To Obtain A Contract [Member]      
Capitalized Contract Cost [Line Items]      
Beginning balance 464.3 455.0  
Capitalization of costs 171.7 166.5  
Amortization (162.4) (157.2)  
Ending balance 473.6 464.3 455.0
Costs To Fulfill A Contract [Member]      
Capitalized Contract Cost [Line Items]      
Beginning balance 66.1 65.4  
Capitalization of costs 24.9 23.7  
Amortization (23.7) (23.0)  
Ending balance $ 67.3 $ 66.1 $ 65.4