Loans - Wholesale Loan Portfolio, Geographic Distribution and Delinquency (Details) - USD ($) $ in Millions	Mar. 31, 2023	Dec. 31, 2022	Mar. 31, 2022
Financing Receivable, Past Due [Line Items]
Retained loans	$ 1,084,850	$ 1,089,598	$ 1,018,397
Wholesale
Financing Receivable, Past Due [Line Items]
Retained loans	604,324	603,670	$ 569,953
Wholesale | Criticized nonaccrual
Financing Receivable, Past Due [Line Items]
Retained loans	2,211	1,963
Wholesale | Current and less than 30 days past due and still accruing
Financing Receivable, Past Due [Line Items]
Retained loans	599,015	599,009
Wholesale | 30–89 days past due and still accruing
Financing Receivable, Past Due [Line Items]
Retained loans	2,957	2,544
Wholesale | 90 or more days past due and still accruing
Financing Receivable, Past Due [Line Items]
Retained loans	141	154
Wholesale | Total U.S.
Financing Receivable, Past Due [Line Items]
Retained loans	482,116	479,589
Wholesale | Total non-U.S.
Financing Receivable, Past Due [Line Items]
Retained loans	122,208	124,081
Wholesale | Secured by real estate
Financing Receivable, Past Due [Line Items]
Retained loans	127,389	126,732
Wholesale | Secured by real estate | Criticized nonaccrual
Financing Receivable, Past Due [Line Items]
Retained loans	338	246
Wholesale | Secured by real estate | Current and less than 30 days past due and still accruing
Financing Receivable, Past Due [Line Items]
Retained loans	126,781	126,083
Wholesale | Secured by real estate | 30–89 days past due and still accruing
Financing Receivable, Past Due [Line Items]
Retained loans	270	402
Wholesale | Secured by real estate | 90 or more days past due and still accruing
Financing Receivable, Past Due [Line Items]
Retained loans	0	1
Wholesale | Secured by real estate | Total U.S.
Financing Receivable, Past Due [Line Items]
Retained loans	124,360	123,740
Wholesale | Secured by real estate | Total non-U.S.
Financing Receivable, Past Due [Line Items]
Retained loans	3,029	2,992
Wholesale | Commercial and industrial
Financing Receivable, Past Due [Line Items]
Retained loans	168,748	167,660
Wholesale | Commercial and industrial | Criticized nonaccrual
Financing Receivable, Past Due [Line Items]
Retained loans	1,263	1,018
Wholesale | Commercial and industrial | Current and less than 30 days past due and still accruing
Financing Receivable, Past Due [Line Items]
Retained loans	166,249	165,415
Wholesale | Commercial and industrial | 30–89 days past due and still accruing
Financing Receivable, Past Due [Line Items]
Retained loans	1,160	1,127
Wholesale | Commercial and industrial | 90 or more days past due and still accruing
Financing Receivable, Past Due [Line Items]
Retained loans	76	100
Wholesale | Commercial and industrial | Total U.S.
Financing Receivable, Past Due [Line Items]
Retained loans	127,826	125,324
Wholesale | Commercial and industrial | Total non-U.S.
Financing Receivable, Past Due [Line Items]
Retained loans	40,922	42,336
Wholesale | Other
Financing Receivable, Past Due [Line Items]
Retained loans	308,187	309,278
Wholesale | Other | Criticized nonaccrual
Financing Receivable, Past Due [Line Items]
Retained loans	610	699
Wholesale | Other | Current and less than 30 days past due and still accruing
Financing Receivable, Past Due [Line Items]
Retained loans	305,985	307,511
Wholesale | Other | 30–89 days past due and still accruing
Financing Receivable, Past Due [Line Items]
Retained loans	1,527	1,015
Wholesale | Other | 90 or more days past due and still accruing
Financing Receivable, Past Due [Line Items]
Retained loans	65	53
Wholesale | Other | Total U.S.
Financing Receivable, Past Due [Line Items]
Retained loans	229,930	230,525
Wholesale | Other | Total non-U.S.
Financing Receivable, Past Due [Line Items]
Retained loans	$ 78,257	$ 78,753