Employee Benefit Plans - 401(k) and Defined Contribution Pension Plans (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Non-U.S. Defined Contribution Pension Plans
Defined Contribution Plans
Expense	$ 149	$ 130	$ 121
Morgan Stanley 401(k) Plan
Defined Contribution Plans
Expense	$ 357	$ 293	$ 280