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Income Taxes - Narrative (Details) - USD ($) $ in Millions | 3 Months Ended | 6 Months Ended
--- | --- | ---
Jun. 30, 2021 | Jun. 30, 2020 | Jun. 30, 2021 | Jun. 30, 2020
Operating Loss Carryforwards [Line Items] |  |  |  |
Statutory rate of income taxes | 21.00% | 21.00% | 21.00% | 21.00%
Separate Return Limitation Year Tax Rules |  |  |  |
Operating Loss Carryforwards [Line Items] |  |  |  |
Operating loss carryforwards subject to SRLY tax rules will expire unutilized at December 31, 2021 | $ 27 |  | $ 27 |

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