XML 77 R53.htm IDEA: XBRL DOCUMENT v3.25.0.1
Summary of Significant Accounting Policies Allowance for Uncollectible Accounts (Details) - USD ($)
$ in Millions
Dec. 31, 2024
Sep. 30, 2024
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Allowance for uncollectible accounts $ 1 $ 1
Financing Receivable, after Allowance for Credit Loss 86 99
Accounts and Financing Receivable, Allowance for Credit Loss 2 2
Reported Value Measurement    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Financing Receivable, after Allowance for Credit Loss $ 94 $ 105