Equity Method Investments - Balances (Details) - Investment Management - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Equity Method Investments
Investments	$ 2,404		$ 2,404		$ 2,432
Income (loss)	$ (16)	$ 4	$ (26)	$ 54

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

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