Business Segments - Segment Operating Results (Parenthetical) (Detail) - USD ($) $ in Millions |
3 Months Ended | 6 Months Ended | ||||
|---|---|---|---|---|---|---|
Jun. 30, 2021 |
Jun. 30, 2020 |
Jun. 30, 2021 |
Jun. 30, 2020 |
Jan. 01, 2021 |
Dec. 31, 2020 |
|
| Product Liability Contingency [Line Items] | ||||||
| Operating expenses | $ 8,640 | $ 10,414 | $ 18,077 | $ 16,872 | ||
| Investment Banking and Global Markets [Member] | ||||||
| Product Liability Contingency [Line Items] | ||||||
| Operating expenses | $ 2,960 | $ 3,140 | ||||
| Standardized Capital Rules [Member] | ||||||
| Product Liability Contingency [Line Items] | ||||||
| Standardized risk based ratios stress capital buffer | 6.60% | 6.60% | 6.60% | 6.60% | ||