Related Party Transactions - Summary of Amounts Included in Condensed Consolidated Statements of Operations Related to Fee for Service Arrangement (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Related Party Transaction [Line Items]
Equity in (losses) earnings from unconsolidated affiliates	$ (1)	$ 1	$ 3	$ 4
BRE Ace LLC
Related Party Transaction [Line Items]
Commissions and other fees	$ 16	$ 31	$ 43	$ 99

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

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