XML 86 R75.htm IDEA: XBRL DOCUMENT v3.25.1
Debt and letter of credit facilities - Letter of Credit Facilities (Details) - Standby letters of credit
Mar. 31, 2025
USD ($)
Line of Credit Facility [Line Items]  
Issued $ 1,130,800,000
Cash and Cash Equivalents  
Line of Credit Facility [Line Items]  
Collateral 23,100,000
Debt securities  
Line of Credit Facility [Line Items]  
Collateral 1,307,300,000
Committed - Secured letters of credit facilities  
Line of Credit Facility [Line Items]  
Committed Capacity 355,000,000.0
Issued 253,200,000
Committed - Secured letters of credit facilities | Cash and Cash Equivalents  
Line of Credit Facility [Line Items]  
Collateral 13,400,000
Committed - Secured letters of credit facilities | Debt securities  
Line of Credit Facility [Line Items]  
Collateral 242,100,000
Uncommitted - Secured letters of credit facilities  
Line of Credit Facility [Line Items]  
Issued 877,600,000
Uncommitted - Secured letters of credit facilities | Cash and Cash Equivalents  
Line of Credit Facility [Line Items]  
Collateral 9,700,000
Uncommitted - Secured letters of credit facilities | Debt securities  
Line of Credit Facility [Line Items]  
Collateral $ 1,065,200,000