v3.26.1
Earnings Per Share - Schedule of Earnings Per Share, Basic and Diluted (Details) - USD ($)
$ / shares in Units, shares in Millions, $ in Millions
 3 Months Ended 6 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Mar. 31, 2026
Mar. 31, 2025
Schedule of Earnings Per Share, Basic and Diluted, by Common Class, Including Two Class Method [Line Items]        
Income Allocation - Basic $ 6,021 $ 4,577 $ 11,874 $ 9,696
Class A common stock        
Schedule of Earnings Per Share, Basic and Diluted, by Common Class, Including Two Class Method [Line Items]        
Income Allocation - Basic $ 5,265 $ 3,996 $ 10,382 $ 8,463
Weighted- Average Shares Outstanding - Basic (in shares) 1,674 1,721 1,681 1,725
Earnings per Share - Basic (in dollars per share) $ 3.15 $ 2.32 $ 6.18 $ 4.90
Income Allocation - Diluted $ 6,021 $ 4,577 $ 11,874 $ 9,696
Weighted- Average Shares Outstanding - Diluted (in shares) 1,916 1,974 1,924 1,979
Earnings per Share - Diluted (in dollars per share) $ 3.14 $ 2.32 $ 6.17 $ 4.90
Class B-1 common stock        
Schedule of Earnings Per Share, Basic and Diluted, by Common Class, Including Two Class Method [Line Items]        
Income Allocation - Basic $ 24 $ 18 $ 46 $ 37
Weighted- Average Shares Outstanding - Basic (in shares) 5 5 5 5
Earnings per Share - Basic (in dollars per share) $ 4.87 $ 3.63 $ 9.58 $ 7.68
Income Allocation - Diluted $ 24 $ 18 $ 46 $ 37
Weighted- Average Shares Outstanding - Diluted (in shares) 5 5 5 5
Earnings per Share - Diluted (in dollars per share) $ 4.87 $ 3.63 $ 9.57 $ 7.67
Class B-2 common stock        
Schedule of Earnings Per Share, Basic and Diluted, by Common Class, Including Two Class Method [Line Items]        
Income Allocation - Basic $ 571 $ 431 $ 1,126 $ 911
Weighted- Average Shares Outstanding - Basic (in shares) 120 120 120 120
Earnings per Share - Basic (in dollars per share) $ 4.75 $ 3.58 $ 9.36 $ 7.57
Income Allocation - Diluted $ 571 $ 430 $ 1,125 $ 909
Weighted- Average Shares Outstanding - Diluted (in shares) 120 120 120 120
Earnings per Share - Diluted (in dollars per share) $ 4.74 $ 3.58 $ 9.35 $ 7.56
Class C common stock        
Schedule of Earnings Per Share, Basic and Diluted, by Common Class, Including Two Class Method [Line Items]        
Income Allocation - Basic $ 112 $ 85 $ 220 $ 183
Weighted- Average Shares Outstanding - Basic (in shares) 9 9 9 9
Earnings per Share - Basic (in dollars per share) $ 12.58 $ 9.29 $ 24.71 $ 19.62
Income Allocation - Diluted $ 112 $ 85 $ 220 $ 183
Weighted- Average Shares Outstanding - Diluted (in shares) 9 9 9 9
Earnings per Share - Diluted (in dollars per share) $ 12.57 $ 9.27 $ 24.68 $ 19.59
Participating securities        
Schedule of Earnings Per Share, Basic and Diluted, by Common Class, Including Two Class Method [Line Items]        
Income Allocation - Basic $ 49 $ 47 $ 100 $ 102
Income Allocation - Diluted $ 49 $ 47 $ 100 $ 102