Loans - Summary of Changes in Allowance for Credit Losses (Detail) - USD ($) $ in Millions |
3 Months Ended | 6 Months Ended | 12 Months Ended | ||
|---|---|---|---|---|---|
Jun. 30, 2021 |
Jun. 30, 2020 |
Jun. 30, 2021 |
Jun. 30, 2020 |
Dec. 31, 2020 |
|
| Allowance for loan losses | |||||
| Balance, beginning of period | $ 3,515 | $ 2,868 | $ 3,874 | $ 2,168 | $ 2,168 |
| Net (charge-offs)/recoveries | (48) | (260) | (126) | (391) | |
| Provision | (193) | 1,434 | (445) | 2,349 | |
| Other | (3) | (141) | (32) | (225) | |
| Balance, end of period | $ 3,271 | $ 3,901 | $ 3,271 | $ 3,901 | $ 3,874 |
| Allowance ratio | 2.70% | 3.70% | 2.70% | 3.70% | 3.70% |
| Net charge-off ratio | 0.20% | 0.90% | 0.20% | 0.80% | 0.90% |
| Allowance for losses on lending commitments | |||||
| Balance, beginning of period | $ 721 | $ 335 | $ 557 | $ 313 | $ 313 |
| Provision | 101 | 155 | 283 | 177 | |
| Other | (18) | ||||
| Balance, end of period | 822 | 490 | 822 | 490 | 557 |
| Wholesale [Member] | |||||
| Allowance for loan losses | |||||
| Balance, beginning of period | 2,408 | 1,943 | 2,584 | 1,331 | 1,331 |
| Net (charge-offs)/recoveries | 8 | (174) | (9) | (224) | |
| Provision | (240) | 1,129 | (370) | 1,875 | |
| Other | (3) | (141) | (32) | (225) | |
| Balance, end of period | $ 2,173 | $ 2,757 | $ 2,173 | $ 2,757 | $ 2,584 |
| Allowance ratio | 2.00% | 2.80% | 2.00% | 2.80% | 2.70% |
| Net charge-off ratio | 0.00% | 0.70% | 0.00% | 0.50% | 0.60% |
| Allowance for losses on lending commitments | |||||
| Balance, beginning of period | $ 541 | $ 335 | $ 557 | $ 313 | $ 313 |
| Provision | 95 | 155 | 97 | 177 | |
| Other | (18) | ||||
| Balance, end of period | 636 | 490 | 636 | 490 | 557 |
| Consumer [Member] | |||||
| Allowance for loan losses | |||||
| Balance, beginning of period | 1,107 | 925 | 1,290 | 837 | 837 |
| Net (charge-offs)/recoveries | (56) | (86) | (117) | (167) | |
| Provision | 47 | 305 | (75) | 474 | |
| Balance, end of period | $ 1,098 | $ 1,144 | $ 1,098 | $ 1,144 | $ 1,290 |
| Allowance ratio | 13.00% | 17.00% | 13.00% | 17.00% | 15.90% |
| Net charge-off ratio | 2.80% | 5.10% | 2.90% | 5.00% | 4.20% |
| Allowance for losses on lending commitments | |||||
| Balance, beginning of period | $ 180 | ||||
| Provision | 6 | $ 186 | $ 0 | ||
| Balance, end of period | $ 186 | $ 186 | |||