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Significant Accounting Policies - Narrative (Details) $ in Millions | 5 Months Ended | 7 Months Ended | 12 Months Ended
--- | --- | --- | ---
Dec. 31, 2018 USD ($) | Jul. 31, 2018 USD ($) | Dec. 31, 2019 USD ($) mortgage_loan | Dec. 31, 2017 USD ($)
Derivative [Line Items] |  |  |  |
Mortgage loans held for investment | mortgage_loan |  |  | 0 |
Mortgage loan sale period |  |  | 30 days |
Number of reporting units |  |  | 3 |
Advertising costs | $ | $ 17 | $ 33 | $ 33 | $ 57
Minimum |  |  |  |
Derivative [Line Items] |  |  |  |
Loan commitment period |  |  | 30 days |
Maximum |  |  |  |
Derivative [Line Items] |  |  |  |
Loan commitment period |  |  | 90 days |

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- Definition The total expense recognized in the period for promotion, public relations, and brand or product advertising. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03.4) -URI http://asc.fasb.org/extlink&oid=116634182&loc=SL114868664-224227 + Details
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