Derivatives and Hedging Activities - Fair Values, Volume of Activity and Gain (Loss) Information Related to Derivative Instruments (Details) - USD ($) $ in Millions	Jun. 30, 2020	Jun. 30, 2019
Derivatives, Fair Value [Line Items]
Notional Amount	$ 135,023	$ 126,077
Derivative assets, netting adjustments	(609)	(473)
Derivative Assets, net	2,090	778
Derivative liabilities, netting adjustments	(629)	(335)
Derivative Liabilities, net	309	156
Derivatives Not Designated as Hedging Instruments
Derivatives, Fair Value [Line Items]
Notional Amount	100,421	86,869
Derivative Assets	2,613	1,062
Derivative Liabilities	934	513
Interest rate \| Derivatives Designated as Hedging Instruments
Derivatives, Fair Value [Line Items]
Notional Amount	34,602	39,208
Derivative Assets	89	191
Derivative Liabilities	5	20
Interest rate \| Derivatives Not Designated as Hedging Instruments
Derivatives, Fair Value [Line Items]
Notional Amount	79,573	71,209
Derivative Assets	1,931	772
Derivative Liabilities	332	233
Foreign exchange \| Derivatives Not Designated as Hedging Instruments
Derivatives, Fair Value [Line Items]
Notional Amount	6,040	6,572
Derivative Assets	108	67
Derivative Liabilities	97	60
Commodity \| Derivatives Not Designated as Hedging Instruments
Derivatives, Fair Value [Line Items]
Notional Amount	6,399	5,324
Derivative Assets	487	208
Derivative Liabilities	462	200
Credit \| Derivatives Not Designated as Hedging Instruments
Derivatives, Fair Value [Line Items]
Notional Amount	591	427
Derivative Assets	4	1
Derivative Liabilities	20	10
Other
Derivatives, Fair Value [Line Items]
Derivative Assets	46
Other \| Derivatives Not Designated as Hedging Instruments
Derivatives, Fair Value [Line Items]
Notional Amount	7,818	3,337
Derivative Assets	83	14
Derivative Liabilities	23	10
Net derivatives
Derivatives, Fair Value [Line Items]
Notional Amount	135,023	126,077
Derivative Assets, net	2,093	780
Derivative Liabilities, net	310	198
Other collateral
Derivatives, Fair Value [Line Items]
Notional Amount	0	0
Derivative Assets, net	(3)	(2)
Derivative Liabilities, net	$ (1)	$ (42)

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