Equity Method Investments - Balances (Details) - Investment Management - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Equity Method Investments
Investments	$ 2,391		$ 2,391		$ 2,432
Income (loss)	$ (13)	$ 8	$ (39)	$ 62

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

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