Deferred Compensation Plans (Performance-Based Stock Units) (Details) - PSUs - $ / shares |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2018 |
Dec. 31, 2017 |
Dec. 31, 2016 |
|
| Share-based Payment Awards | |||
| Terms of award | PSUs will vest and convert to shares of common stock only if the Firm satisfies predetermined performance and market-based conditions over a three-year performance period. | ||
| Non-option awards outstanding (shares) | 3,000,000 | ||
| Minimum | |||
| Share-based Payment Awards | |||
| Percentage of PSUs that vested | 0.00% | ||
| Maximum | |||
| Share-based Payment Awards | |||
| Percentage of PSUs that vested | 150.00% | ||
| MS Adjusted ROE | |||
| Share-based Payment Awards | |||
| Fair value per PSU on award date | $ 56.84 | $ 42.64 | $ 25.19 |
| Relative MS TSR | |||
| Share-based Payment Awards | |||
| Fair value per PSU on award date | $ 65.81 | $ 48.02 | $ 24.51 |