v3.26.1
Accumulated Other Comprehensive Income (Loss) (Details) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Mar. 31, 2026
Mar. 31, 2025
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]        
Beginning Balance     $ 12,954  
Aggregate adjustment for the period $ 137 $ (72) 149 $ (207)
Ending Balance 13,543 17,032 13,543 17,032
AOCI Attributable to Parent        
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]        
Beginning Balance (631) (1,044) (642) (964)
Aggregate adjustment for the period 137 (84) 148 (164)
Ending Balance (494) (1,128) (494) (1,128)
Foreign currency translation adjustments        
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]        
Beginning Balance (633) (1,041) (638) (956)
Aggregate adjustment for the period 140 (90) 145 (175)
Ending Balance (493) (1,131) (493) (1,131)
Other        
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]        
Beginning Balance 2 (3) (4) (8)
Current period changes in fair value 6 8 16 16
Reclassification to income (8) (2) (12) (4)
Net tax impact (1) 0 (1) (1)
Ending Balance $ (1) $ 3 $ (1) $ 3