v3.26.1
Shareholders' Equity (Narrative) (Details)
$ / shares in Units, $ in Millions
 3 Months Ended 12 Months Ended 36 Months Ended
Apr. 20, 2026
$ / shares
Dec. 15, 2025
shares
Oct. 31, 2025
shares
Mar. 11, 2025
shares
Oct. 30, 2024
shares
Dec. 13, 2023
$ / shares
Oct. 31, 2023
$ / shares
Mar. 31, 2026
$ / shares
Dec. 31, 2025
USD ($)
shares
Sep. 30, 2025
USD ($)
shares
Mar. 31, 2025
USD ($)
shares
Sep. 30, 2024
USD ($)
shares
Dec. 31, 2023
$ / shares
Sep. 30, 2023
$ / shares
Jun. 30, 2026
USD ($)
shares
Jun. 30, 2025
USD ($)
shares
Jun. 30, 2024
USD ($)
shares
Jun. 30, 2023
USD ($)
Class of Stock [Line Items]                                    
Treasury Stock, Value, Acquired, Cost Method | $                             $ 1,364 $ 757 $ 759  
Share repurchase program activity | $                             $ 1,358 $ 765 750  
Common shares, authorized                             755,000,000 755,000,000    
Preferred shares, authorized                             500,000 500,000    
Share Repurchase Programs                                    
Class of Stock [Line Items]                                    
Share Repurchase Program, Excise Tax | $                             $ 8 $ 15    
$375 million share repurchase program                                    
Class of Stock [Line Items]                                    
Share repurchase program activity | $                 $ 375 $ 375 $ 375 $ 375            
Common Class A                                    
Class of Stock [Line Items]                                    
Common shares, authorized                             750,000,000 750,000,000    
Common Stock, Voting Rights, Votes                             1      
Common Class B                                    
Class of Stock [Line Items]                                    
Common shares, authorized                             5,000,000 5,000,000    
Treasury Shares                                    
Class of Stock [Line Items]                                    
Treasury Stock, Value, Acquired, Cost Method | $                             $ 1,364 $ 757 $ 859  
Treasury Stock, Shares, Acquired                             7,000,000 6,000,000 9,000,000  
Share repurchase program activity | $                                   $ 2,900
Treasury Stock, Shares, Retired                               56,000,000    
Treasury Shares | $375 million share repurchase program                                    
Class of Stock [Line Items]                                    
Treasury Stock, Shares, Acquired   300,000 400,000 600,000 700,000       1,600,000 2,000,000.0 2,400,000 2,700,000            
Treasury Shares | $500 million share repurchase program [Member]                                    
Class of Stock [Line Items]                                    
Treasury shares acquired, average price per share (in usd per share) | $ / shares             $ 88.22             $ 90.57        
Treasury Shares | $250 million share repurchase program                                    
Class of Stock [Line Items]                                    
Treasury shares acquired, average price per share (in usd per share) | $ / shares $ 209.55         $ 103.67   $ 215.42         $ 101.66