Loans - Wholesale Loan Portfolio, Internal Risk Ratings (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Dec. 31, 2022
Accounts, Notes, Loans and Financing Receivable [Line Items]
Retained loans	$ 1,084,850	$ 1,018,397	$ 1,089,598
Loans by origination year
Total retained loans	1,084,850	1,018,397	1,089,598
Gross charge-offs by origination year
Total gross charge-offs	1,451	976
Wholesale
Accounts, Notes, Loans and Financing Receivable [Line Items]
Retained loans	$ 604,324	569,953	$ 603,670
% of investment-grade to total retained loans	70.30%		70.47%
% of total criticized to total retained loans	2.89%		2.60%
% of criticized nonaccrual to total retained loans	0.37%		0.33%
Loans by origination year
Total retained loans	$ 604,324	569,953	$ 603,670
Gross charge-offs by origination year
Total gross charge-offs	105	$ 52
Wholesale | Investment-grade
Accounts, Notes, Loans and Financing Receivable [Line Items]
Retained loans	424,855		425,412
Loans by origination year
Total retained loans	424,855		425,412
Wholesale | Total noninvestment-grade
Accounts, Notes, Loans and Financing Receivable [Line Items]
Retained loans	179,469		178,258
Loans by origination year
Total retained loans	179,469		178,258
Wholesale | Noncriticized
Accounts, Notes, Loans and Financing Receivable [Line Items]
Retained loans	162,029		162,553
Loans by origination year
Total retained loans	162,029		162,553
Wholesale | Criticized performing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Retained loans	15,229		13,742
Loans by origination year
Total retained loans	15,229		13,742
Wholesale | Criticized nonaccrual
Accounts, Notes, Loans and Financing Receivable [Line Items]
Retained loans	2,211		1,963
Loans by origination year
Total retained loans	2,211		1,963
Wholesale | Secured by real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Retained loans	$ 127,389		$ 126,732
% of investment-grade to total retained loans	77.95%		78.55%
% of total criticized to total retained loans	3.56%		3.08%
% of criticized nonaccrual to total retained loans	0.27%		0.19%
Loans by origination year
Term loans originated in 2023/2022	$ 2,530		$ 30,206
Term loans originated in 2022/2021	30,521		28,009
Term loans originated in 2021/2020	28,175		17,805
Term loans originated in 2020/2019	17,302		18,164
Term loans originated in 2019/2018	17,899		7,672
Term loans originated prior to 2019/2018	29,145		22,948
Revolving loans within the revolving period	1,816		1,926
Revolving loans converted to term loans	1		2
Total retained loans	127,389		126,732
Gross charge-offs by origination year
Gross charge-offs originated in 2023	0
Gross charge-offs originated in 2022	0
Gross charge-offs originated in 2021	0
Gross charge-offs originated in 2020	0
Gross charge-offs originated in 2019	0
Gross charge-offs originated prior to 2019	8
Gross charge-offs originated within the revolving period	0
Gross charge-offs originated converted to term loans	0
Total gross charge-offs	8
Wholesale | Secured by real estate | Investment-grade
Accounts, Notes, Loans and Financing Receivable [Line Items]
Retained loans	99,301		99,552
Loans by origination year
Term loans originated in 2023/2022	1,691		24,134
Term loans originated in 2022/2021	23,975		22,407
Term loans originated in 2021/2020	22,370		14,773
Term loans originated in 2020/2019	14,280		14,666
Term loans originated in 2019/2018	14,266		5,277
Term loans originated prior to 2019/2018	21,517		17,289
Revolving loans within the revolving period	1,202		1,006
Revolving loans converted to term loans	0		0
Total retained loans	99,301		99,552
Wholesale | Secured by real estate | Total noninvestment-grade
Accounts, Notes, Loans and Financing Receivable [Line Items]
Retained loans	28,088		27,180
Loans by origination year
Term loans originated in 2023/2022	839		6,072
Term loans originated in 2022/2021	6,546		5,602
Term loans originated in 2021/2020	5,805		3,032
Term loans originated in 2020/2019	3,022		3,498
Term loans originated in 2019/2018	3,633		2,395
Term loans originated prior to 2019/2018	7,628		5,659
Revolving loans within the revolving period	614		920
Revolving loans converted to term loans	1		2
Total retained loans	28,088		27,180
Wholesale | Secured by real estate | Noncriticized
Accounts, Notes, Loans and Financing Receivable [Line Items]
Retained loans	23,550		23,272
Loans by origination year
Total retained loans	23,550		23,272
Wholesale | Secured by real estate | Criticized performing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Retained loans	4,200		3,662
Loans by origination year
Total retained loans	4,200		3,662
Wholesale | Secured by real estate | Criticized nonaccrual
Accounts, Notes, Loans and Financing Receivable [Line Items]
Retained loans	$ 338		$ 246
% of criticized nonaccrual to total retained loans	0.27%		0.19%
Loans by origination year
Total retained loans	$ 338		$ 246
Wholesale | Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Retained loans	$ 168,748		$ 167,660
% of investment-grade to total retained loans	45.51%		45.49%
% of total criticized to total retained loans	6.49%		5.96%
% of criticized nonaccrual to total retained loans	0.75%		0.61%
Loans by origination year
Term loans originated in 2023/2022	$ 14,525		$ 45,160
Term loans originated in 2022/2021	34,578		20,782
Term loans originated in 2021/2020	18,728		6,504
Term loans originated in 2020/2019	5,631		4,501
Term loans originated in 2019/2018	3,550		1,273
Term loans originated prior to 2019/2018	2,859		2,003
Revolving loans within the revolving period	88,793		87,354
Revolving loans converted to term loans	84		83
Total retained loans	168,748		167,660
Gross charge-offs by origination year
Gross charge-offs originated in 2023	0
Gross charge-offs originated in 2022	0
Gross charge-offs originated in 2021	16
Gross charge-offs originated in 2020	1
Gross charge-offs originated in 2019	2
Gross charge-offs originated prior to 2019	3
Gross charge-offs originated within the revolving period	63
Gross charge-offs originated converted to term loans	1
Total gross charge-offs	86
Wholesale | Commercial and industrial | Investment-grade
Accounts, Notes, Loans and Financing Receivable [Line Items]
Retained loans	76,797		76,275
Loans by origination year
Term loans originated in 2023/2022	8,780		21,072
Term loans originated in 2022/2021	14,073		8,338
Term loans originated in 2021/2020	7,567		3,045
Term loans originated in 2020/2019	2,643		1,995
Term loans originated in 2019/2018	1,396		748
Term loans originated prior to 2019/2018	1,450		989
Revolving loans within the revolving period	40,887		40,087
Revolving loans converted to term loans	1		1
Total retained loans	76,797		76,275
Wholesale | Commercial and industrial | Total noninvestment-grade
Accounts, Notes, Loans and Financing Receivable [Line Items]
Retained loans	91,951		91,385
Loans by origination year
Term loans originated in 2023/2022	5,745		24,088
Term loans originated in 2022/2021	20,505		12,444
Term loans originated in 2021/2020	11,161		3,459
Term loans originated in 2020/2019	2,988		2,506
Term loans originated in 2019/2018	2,154		525
Term loans originated prior to 2019/2018	1,409		1,014
Revolving loans within the revolving period	47,906		47,267
Revolving loans converted to term loans	83		82
Total retained loans	91,951		91,385
Wholesale | Commercial and industrial | Noncriticized
Accounts, Notes, Loans and Financing Receivable [Line Items]
Retained loans	80,992		81,393
Loans by origination year
Total retained loans	80,992		81,393
Wholesale | Commercial and industrial | Criticized performing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Retained loans	9,696		8,974
Loans by origination year
Total retained loans	9,696		8,974
Wholesale | Commercial and industrial | Criticized nonaccrual
Accounts, Notes, Loans and Financing Receivable [Line Items]
Retained loans	1,263		1,018
Loans by origination year
Total retained loans	1,263		1,018
Wholesale | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Retained loans	$ 308,187		$ 309,278
% of investment-grade to total retained loans	80.72%		80.70%
% of total criticized to total retained loans	0.63%		0.58%
% of criticized nonaccrual to total retained loans	0.20%		0.23%
Loans by origination year
Term loans originated in 2023/2022	$ 13,134		$ 48,950
Term loans originated in 2022/2021	39,867		22,960
Term loans originated in 2021/2020	21,078		14,836
Term loans originated in 2020/2019	14,051		5,228
Term loans originated in 2019/2018	5,062		2,610
Term loans originated prior to 2019/2018	8,988		7,726
Revolving loans within the revolving period	203,146		203,289
Revolving loans converted to term loans	2,861		3,679
Total retained loans	308,187		309,278
Gross charge-offs by origination year
Gross charge-offs originated in 2023	0
Gross charge-offs originated in 2022	0
Gross charge-offs originated in 2021	5
Gross charge-offs originated in 2020	5
Gross charge-offs originated in 2019	0
Gross charge-offs originated prior to 2019	0
Gross charge-offs originated within the revolving period	1
Gross charge-offs originated converted to term loans	0
Total gross charge-offs	11
Wholesale | Other | Investment-grade
Accounts, Notes, Loans and Financing Receivable [Line Items]
Retained loans	248,757		249,585
Loans by origination year
Term loans originated in 2023/2022	10,340		32,121
Term loans originated in 2022/2021	25,435		15,864
Term loans originated in 2021/2020	14,913		13,015
Term loans originated in 2020/2019	12,359		4,529
Term loans originated in 2019/2018	4,370		2,159
Term loans originated prior to 2019/2018	8,158		7,251
Revolving loans within the revolving period	170,325		171,049
Revolving loans converted to term loans	2,857		3,597
Total retained loans	248,757		249,585
Wholesale | Other | Total noninvestment-grade
Accounts, Notes, Loans and Financing Receivable [Line Items]
Retained loans	59,430		59,693
Loans by origination year
Term loans originated in 2023/2022	2,794		16,829
Term loans originated in 2022/2021	14,432		7,096
Term loans originated in 2021/2020	6,165		1,821
Term loans originated in 2020/2019	1,692		699
Term loans originated in 2019/2018	692		451
Term loans originated prior to 2019/2018	830		475
Revolving loans within the revolving period	32,821		32,240
Revolving loans converted to term loans	4		82
Total retained loans	59,430		59,693
Wholesale | Other | Noncriticized
Accounts, Notes, Loans and Financing Receivable [Line Items]
Retained loans	57,487		57,888
Loans by origination year
Total retained loans	57,487		57,888
Wholesale | Other | Criticized performing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Retained loans	1,333		1,106
Loans by origination year
Total retained loans	1,333		1,106
Wholesale | Other | Criticized nonaccrual
Accounts, Notes, Loans and Financing Receivable [Line Items]
Retained loans	610		699
Loans by origination year
Total retained loans	$ 610		$ 699