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Fair Value (Narrative) (Details) - USD ($) $ in Millions | 6 Months Ended
--- | ---
Jun. 30, 2021 | Jun. 30, 2020
Fair Value [Line Items] |  |
Transfers Into Level 3 | $ 0 | $ 0
Transfers out of Level 3 | 0 | 0
Significant fair value adjustments for assets and liabilities measured on a nonrecurring basis | $ 0 | $ 0

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- Definition Fair Value Adjustments For Nonfinancial Assets And Liabilities Measured At Fair Value Or Financial Assets and Liabilities On Non Recurring Basis + References No definition available. + Details
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Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
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Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

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- Definition Amount of transfer of financial instrument classified as an asset into level 3 of the fair value hierarchy. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(3) -URI http://asc.fasb.org/extlink&oid=123874694&loc=d3e19207-110258 + Details
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Balance Type: | debit
Period Type: | duration

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- Definition Amount of transfers of financial instrument classified as an asset out of level 3 of the fair value hierarchy. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(3) -URI http://asc.fasb.org/extlink&oid=123874694&loc=d3e19207-110258 + Details
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Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration