Other Assets - Equity Method Investments - Joint Ventures (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
MUMSS
Equity Method Investments
Income (loss) from investment in MUMSS	$ 14	$ 52	$ 18	$ 84

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

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