Summary of Significant Accounting Policies - Schedule Of Allowance For Uncollectible Accounts (Details) - USD ($) $ in Millions |
12 Months Ended | ||
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Dec. 31, 2019 |
Dec. 31, 2018 |
Dec. 31, 2017 |
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| 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 |
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- Definition A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period. No definition available.
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- Definition Amount of expense (reversal of expense) for expected credit loss on premium receivable. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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- Definition The carrying value as of the balance sheet date of the estimated valuation allowance to reduce gross premiums receivable to net realizable value. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Amount of writeoff of premium receivable, charged against allowance for credit loss. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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