Nature of Business and Basis of Presentation - Narrative (Details) - USD ($) $ in Millions	Feb. 01, 2019	Dec. 31, 2020	Jan. 01, 2020	Dec. 31, 2019	Dec. 31, 2018	Aug. 01, 2018	Jul. 31, 2018	Dec. 31, 2017
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total stockholders’ equity		$ 2,504		$ 2,231	$ 1,945	$ 1,056	$ 1,883	$ 1,722
Pacific Union Financial, LLC
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cash consideration	$ 116
Cumulative Effect, Period of Adoption, Adjustment
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total stockholders’ equity				7
Cumulative Effect, Period of Adoption, Adjustment | Advances and Other Receivables Reserve
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Allowance for credit losses			$ 7
Cumulative Effect, Period of Adoption, Adjustment | Other Assets
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Allowance for credit losses			2
Retained Earnings
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total stockholders’ equity		$ 1,434		1,122	$ 848	$ (36)	$ 885	$ 731
Retained Earnings | Cumulative Effect, Period of Adoption, Adjustment
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total stockholders’ equity			9	$ 7
Retained Earnings | Cumulative Effect, Period of Adoption, Adjustment After Tax
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total stockholders’ equity			$ 7