Annual report pursuant to Section 13 and 15(d)

Summary of Significant Accounting Policies - Schedule Of Allowance For Uncollectible Accounts (Details)

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Summary of Significant Accounting Policies - Schedule Of Allowance For Uncollectible Accounts (Details) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Accounts Receivable, Allowance for Credit Loss [Roll Forward]      
Allowances, beginning of year $ 123 $ 24 $ 29
Amounts charged to expense 76 134 35
Write-offs of uncollectible receivables (42) (35) (40)
Allowances, end of year $ 157 $ 123 $ 24