Other Assets (Details) - USD ($) $ in Millions	Mar. 31, 2020	Dec. 31, 2019
Components of Other Assets [Line Items]
Corporate/bank-owned life insurance	$ 20,128	$ 20,070
Accounts receivable	46,762	29,137
Interest receivable, AFS and HTM debt securities	1,705	1,729
Interest receivable, loans	3,038	3,099
Interest receivable, trading and other	708	758
Net carrying value	1,805	1,853
Foreclosed assets, other	72	81
Operating lease ROU assets (lessee)	4,650	4,724
Due from customers on acceptances	128	253
Other	10,269	10,200
Total other assets	96,163	78,917
Assets leased to others [Member]
Components of Other Assets [Line Items]
Other	8,124	8,221
Non-government insured/guaranteed [Member]
Components of Other Assets [Line Items]
Foreclosed assets, residential real estate	137	172
Government insured or guaranteed [Member]
Components of Other Assets [Line Items]
Foreclosed assets, residential real estate	43	50
Customer relationship and other amortized intangibles [Member]
Components of Other Assets [Line Items]
Net carrying value	$ 399	$ 423