Related Parties - Management Fees Incurred (Details) - Related Party - Asset management fees - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Related Party Transaction [Line Items]
Due to related parties	$ 31		$ 31		$ 42
Expenses from transactions with related parties	$ 111	$ 127	$ 362	$ 313