Related Party Transactions - Summary of Amounts Included in Condensed Consolidated Statements of Operations Related to Fee for Service Arrangement (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Related Party Transaction [Line Items]
Equity in earnings from unconsolidated affiliates	$ 4		$ 1
BRE Ace LLC
Related Party Transaction [Line Items]
Equity in earnings from unconsolidated affiliates	4		1
Commission and other fees	$ 136	$ 132	$ 79

Amount of income (loss) for proportionate share of equity method investee's income (loss).

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