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Fair Value Measurements - Narrative (Details) - USD ($) $ in Millions | 9 Months Ended |
--- | --- | ---
Sep. 30, 2021 | Dec. 31, 2020
Fair Value of Financial Instruments [Line Items] |  |
Investments not required to be disclosed | $ 349 | $ 322
NUG contracts |  |
Fair Value of Financial Instruments [Line Items] |  |
Period of future observable data to determine contract price | 2 years |

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- Definition Derivative, Contract Price, Period of Future Observable Data + References No definition available. + Details
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- Definition Investments not required to be disclosed. + References No definition available. + Details
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Balance Type: | debit
Period Type: | instant

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- Details
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Balance Type: |
Period Type: |