v3.26.1
FINANCIAL RISK MANAGEMENT - Credit Risk (Details) - CAD ($)
$ in Millions
Mar. 31, 2026
Mar. 31, 2025
Disclosure of detailed information about financial instruments [line items]    
Gross accounts receivable $ 646.7 $ 633.3
Gross contract assets 522.6 521.0
Total $ 1,169.3 $ 1,154.3
Expected credit loss rate (in percent) 1.90% 1.80%
Accumulated impairment    
Disclosure of detailed information about financial instruments [line items]    
Credit loss allowances $ (22.4) $ (21.3)
Civil Aviation    
Disclosure of detailed information about financial instruments [line items]    
Gross accounts receivable 350.0 384.8
Gross contract assets 157.8 163.2
Total $ 507.8 $ 548.0
Expected credit loss rate (in percent) 4.30% 3.50%
Civil Aviation | Accumulated impairment    
Disclosure of detailed information about financial instruments [line items]    
Credit loss allowances $ (21.9) $ (19.3)
Defense and Security    
Disclosure of detailed information about financial instruments [line items]    
Gross accounts receivable 254.3 211.8
Gross contract assets 364.7 357.8
Total $ 619.0 $ 569.6
Expected credit loss rate (in percent) 0.10% 0.40%
Defense and Security | Accumulated impairment    
Disclosure of detailed information about financial instruments [line items]    
Credit loss allowances $ (0.5) $ (2.0)
Amounts not allocated to a segment    
Disclosure of detailed information about financial instruments [line items]    
Gross accounts receivable 42.4 36.7
Gross contract assets 0.0 0.0
Total $ 42.4 $ 36.7
Expected credit loss rate (in percent) 0.00% 0.00%
Amounts not allocated to a segment | Accumulated impairment    
Disclosure of detailed information about financial instruments [line items]    
Credit loss allowances $ 0.0 $ 0.0