v3.26.1
Capitalization (Schedule of Changes in Common Stock Equity) (Details) - USD ($)
$ / shares in Units, $ in Thousands
 3 Months Ended 9 Months Ended
Dec. 17, 2025
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Increase (Decrease) in Stockholders' Equity [Roll Forward]          
Beginning balance (in shares)       90,379,095  
Beginning balance       $ 3,094,604  
Net Income Available for Common Stock   $ 138,621 $ 149,818 567,934 $ 411,162
Dividends Declared on Common Stock   (52,745) (48,340) (154,419) (141,566)
Other Comprehensive Income (Loss), Net of Tax   $ 8,465 $ 107,168 $ 68,798 $ (100,331)
Ending balance (in shares)   95,035,675   95,035,675  
Ending balance   $ 3,923,679   $ 3,923,679  
Dividends per share (in dollars per share)   $ 0.555 $ 0.535 $ 1.625 $ 1.565
Stock and Benefit Plans          
Increase (Decrease) in Stockholders' Equity [Roll Forward]          
Common Stock Issued Under Stock and Benefit Plans (in shares)       254,067  
Sale of Common Stock          
Increase (Decrease) in Stockholders' Equity [Roll Forward]          
Common Stock Issued from Sale of Common Stock (in shares) 4,402,513     4,402,513  
Common Stock          
Increase (Decrease) in Stockholders' Equity [Roll Forward]          
Beginning balance (in shares)   95,027,000 90,398,000 90,379,000 91,006,000
Beginning balance   $ 95,027 $ 90,398 $ 90,379 $ 91,006
Common Stock Issued Under Stock and Benefit Plans (in shares)   9,000 12,000 254,000 179,000
Common Stock Issued Under Stock and Benefit Plans   $ 9 $ 12 $ 254 $ 179
Ending balance (in shares)   95,036,000 90,356,000 95,036,000 90,356,000
Ending balance   $ 95,036 $ 90,356 $ 95,036 $ 90,356
Common Stock | Share Repurchase Plan          
Increase (Decrease) in Stockholders' Equity [Roll Forward]          
Share Repurchases (in shares)     (54,000)   (829,000)
Share Repurchases     $ (54)   $ (829)
Common Stock | Sale of Common Stock          
Increase (Decrease) in Stockholders' Equity [Roll Forward]          
Common Stock Issued from Sale of Common Stock (in shares)   0   4,403,000  
Common Stock Issued from Sale of Common Stock   $ 0   $ 4,403  
Paid In Capital          
Increase (Decrease) in Stockholders' Equity [Roll Forward]          
Beginning balance   1,388,193 1,042,822 1,050,918 1,045,487
Share-Based Payment Expense [1]   4,134 4,685 12,680 13,911
Ending balance   1,393,023 1,047,406 1,393,023 1,047,406
Paid In Capital | Stock and Benefit Plans          
Increase (Decrease) in Stockholders' Equity [Roll Forward]          
Common Stock Issued Under Stock and Benefit Plans   703 529    
Share Repurchases       (4,568) (2,377)
Paid In Capital | Share Repurchase Plan          
Increase (Decrease) in Stockholders' Equity [Roll Forward]          
Share Repurchases     (630)   (9,615)
Paid In Capital | Sale of Common Stock          
Increase (Decrease) in Stockholders' Equity [Roll Forward]          
Common Stock Issued from Sale of Common Stock   (7)   333,993  
Earnings Reinvested in the Business          
Increase (Decrease) in Stockholders' Equity [Roll Forward]          
Beginning balance   2,340,168 1,855,366 2,012,529 1,727,326
Net Income Available for Common Stock   138,621 149,818 567,934 411,162
Dividends Declared on Common Stock   (52,745) (48,340) (154,419) (141,566)
Share Repurchases   0 (3,311) 0 (43,389)
Ending balance   2,426,044 1,953,533 2,426,044 1,953,533
Earnings Reinvested in the Business | Share Repurchase Plan          
Increase (Decrease) in Stockholders' Equity [Roll Forward]          
Share Repurchases     (3,311)   (43,389)
Accumulated Other Comprehensive Income (Loss)          
Increase (Decrease) in Stockholders' Equity [Roll Forward]          
Beginning balance   1,111 (222,975) (59,222) (15,476)
Other Comprehensive Income (Loss), Net of Tax   8,465 107,168 68,798 (100,331)
Ending balance   $ 9,576 $ (115,807) $ 9,576 $ (115,807)
[1] Paid in Capital includes compensation costs associated with performance shares and/or restricted stock awards. The expense is included within Net Income Available For Common Stock, net of tax benefits.