Regulatory Capital Requirements (Risk-adjusted Capital Amounts and Ratios, United States of America, MUAH) (Detail) - U.S. Basel III
$ in Millions |
Dec. 31, 2021
USD ($)
|
Dec. 31, 2020
USD ($)
|
Jan. 01, 2019 |
| BK (US) |
|
|
|
| Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items] |
|
|
|
| Total capital (to risk-weighted assets): Actual amount |
$ 16,265
|
$ 15,629
|
|
| Tier 1 capital (to risk-weighted assets): Actual amount |
15,629
|
14,634
|
|
| Tier 1 capital (to quarterly average assets): Actual amount |
15,629
|
14,634
|
|
| Common Equity Tier 1 capital (to risk-weighted assets): Actual amount |
$ 15,629
|
$ 14,634
|
|
| Total capital (to risk-weighted assets): Actual ratio |
0.1736
|
0.1668
|
|
| Tier 1 capital (to risk-weighted assets): Actual ratio |
0.1668
|
0.1562
|
|
| Tier 1 capital (to quarterly average assets): Actual ratio |
0.1214
|
0.1112
|
|
| Common Equity Tier 1 capital (to risk-weighted assets): Actual ratio |
0.1668
|
0.1562
|
|
| Total capital (to risk-weighted assets): Amount for minimum capital ratios required |
$ 9,840
|
$ 9,836
|
|
| Tier 1 capital (to risk-weighted assets): Amount for minimum capital ratios required |
7,966
|
7,963
|
|
| Tier 1 capital (to quarterly average assets): Amount for minimum capital ratios required |
5,149
|
5,262
|
|
| Common Equity Tier 1 capital (to risk-weighted assets): Amount for minimum capital ratios required |
$ 6,560
|
$ 6,557
|
|
| Total capital (to risk-weighted assets): Ratio for minimum capital ratios required |
0.1050
|
0.1050
|
|
| Tier 1 capital (to risk-weighted assets): Ratio for minimum capital ratios required |
0.0850
|
0.0850
|
|
| Tier 1 capital (to quarterly average assets): Ratio for minimum capital ratios required |
0.0400
|
0.0400
|
|
| Common Equity Tier 1 capital (to risk-weighted assets): Ratio for minimum capital ratios required |
0.0700
|
0.0700
|
|
| Total capital (to risk-weighted assets): Amount OCC requires to be "well capitalized" |
$ 9,371
|
$ 9,368
|
|
| Tier 1 capital (to risk-weighted assets): Amount OCC requires to be "well capitalized" |
7,497
|
7,494
|
|
| Tier 1 capital (to quarterly average assets): Amount OCC requires to be "well capitalized" |
6,436
|
6,577
|
|
| Common Equity Tier 1 capital (to risk-weighted assets): Amount OCC requires to be "well capitalized" |
$ 6,091
|
$ 6,089
|
|
| Total capital (to risk-weighted assets): Ratios OCC requires to be "well capitalized" |
0.1000
|
0.1000
|
|
| Tier 1 capital (to risk-weighted assets): Ratios OCC requires to be "well capitalized" |
0.0800
|
0.0800
|
|
| Tier 1 capital (to quarterly average assets): Ratios OCC requires to be "well capitalized" |
0.0500
|
0.0500
|
|
| Common Equity Tier 1 capital (to risk-weighted assets): Ratios OCC requires to be "well capitalized" |
0.0650
|
0.0650
|
|
| Capital conservation buffer |
|
|
2.50%
|
| MUAH |
|
|
|
| Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items] |
|
|
|
| Total capital (to risk-weighted assets): Actual amount |
$ 17,177
|
$ 16,871
|
|
| Tier 1 capital (to risk-weighted assets): Actual amount |
16,843
|
15,823
|
|
| Tier 1 capital (to quarterly average assets): Actual amount |
16,843
|
15,823
|
|
| Common Equity Tier 1 capital (to risk-weighted assets): Actual amount |
$ 16,843
|
$ 15,823
|
|
| Total capital (to risk-weighted assets): Actual ratio |
0.1632
|
0.1629
|
|
| Tier 1 capital (to risk-weighted assets): Actual ratio |
0.1601
|
0.1528
|
|
| Tier 1 capital (to quarterly average assets): Actual ratio |
0.1044
|
0.0956
|
|
| Common Equity Tier 1 capital (to risk-weighted assets): Actual ratio |
0.1601
|
0.1528
|
|
| Total capital (to risk-weighted assets): Amount for minimum capital ratios required |
$ 11,890
|
$ 12,843
|
|
| Tier 1 capital (to risk-weighted assets): Amount for minimum capital ratios required |
9,786
|
10,772
|
|
| Tier 1 capital (to quarterly average assets): Amount for minimum capital ratios required |
6,453
|
6,623
|
|
| Common Equity Tier 1 capital (to risk-weighted assets): Amount for minimum capital ratios required |
$ 8,208
|
$ 9,218
|
|
| Total capital (to risk-weighted assets): Ratio for minimum capital ratios required |
0.1130
|
0.1240
|
|
| Tier 1 capital (to risk-weighted assets): Ratio for minimum capital ratios required |
0.0930
|
0.1040
|
|
| Tier 1 capital (to quarterly average assets): Ratio for minimum capital ratios required |
0.0400
|
0.0400
|
|
| Common Equity Tier 1 capital (to risk-weighted assets): Ratio for minimum capital ratios required |
0.0780
|
0.0890
|
|
| Capital conservation buffer |
3.30%
|
4.40%
|
|