v3.26.1
Investments - Schedule of Amounts Recorded in Other Comprehensive Income (Details) - USD ($)
$ in Millions
12 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Mar. 31, 2024
Disclosure Of Analysis Of Other Comprehensive Income By Item [Line Items]      
Other comprehensive income, Gross $ 2    
Other comprehensive income, Net [1] (2) $ 24 $ 17
Quoted Debt Securities      
Disclosure Of Analysis Of Other Comprehensive Income By Item [Line Items]      
Other comprehensive income, Gross   26 19
Other comprehensive income, Tax   (3) (2)
Other comprehensive income, Net   23 17
Certificates of Deposit and Commercial Papers      
Disclosure Of Analysis Of Other Comprehensive Income By Item [Line Items]      
Other comprehensive income, Gross   1  
Other comprehensive income, Tax   0  
Other comprehensive income, Net   1  
Certificates of Deposit, Commercial Papers and Quoted Debt Securities      
Disclosure Of Analysis Of Other Comprehensive Income By Item [Line Items]      
Other comprehensive income, Gross (3)    
Other comprehensive income, Tax 1    
Other comprehensive income, Net (2)    
Equity And Preference Securities      
Disclosure Of Analysis Of Other Comprehensive Income By Item [Line Items]      
Other comprehensive income, Gross 49 2 1
Other comprehensive income, Tax (7) 0 1
Other comprehensive income, Net $ 42 $ 2 $ 2
[1] net of taxes