Derivatives and Hedging Activities - Fair Values, Volume of Activity and Gain (Loss) Information Related to Derivative Instruments (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Derivatives, Fair Value [Line Items]
Notional Amount	$ 114,065	$ 102,645
Derivative assets, netting adjustments	(324)	(333)
Derivative Assets, net	524	529
Derivative liabilities, netting adjustments	(336)	(337)
Derivative Liabilities, net	157	353
Derivatives Designated as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	32,962	28,668
Derivative Assets	24	52
Derivative Liabilities	10	(10)
Derivatives Not Designated as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	81,103	73,977
Derivative Assets	826	812
Derivative Liabilities	529	733
Interest Rate [Member] \| Derivatives Designated as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	32,840	28,546
Derivative Assets	24	50
Derivative Liabilities	10	(10)
Interest Rate [Member] \| Derivatives Not Designated as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	65,136	63,454
Derivative Assets	505	365
Derivative Liabilities	227	307
Foreign Exchange [Member] \| Derivatives Designated as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	122	122
Derivative Assets	0	2
Derivative Liabilities	0	0
Foreign Exchange [Member] \| Derivatives Not Designated as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	5,664	6,829
Derivative Assets	76	104
Derivative Liabilities	68	95
Commodity [Member] \| Derivatives Not Designated as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	6,622	2,002
Derivative Assets	233	333
Derivative Liabilities	223	323
Credit [Member] \| Derivatives Not Designated as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	415	226
Derivative Assets	1	1
Derivative Liabilities	3	1
Other [Member] \| Derivatives Not Designated as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	3,266	1,466
Derivative Assets	11	9
Derivative Liabilities	8	7
Net Derivatives [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	114,065	102,645
Derivative Assets, net	526	531
Derivative Liabilities, net	203	386
Counterparty And Cash Collateral Netting [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	0	0
Derivative Assets, net	(2)	(2)
Derivative Liabilities, net	$ (46)	$ (33)

Aggregate notional amount specified by the derivative(s). Expressed as an absolute value.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Article 12
-Section 13
-Sentence Column B

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