Securitizations and Variable Interest Entities, Unconsolidated VIEs (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Variable Interest Entity [Line Items]
Total VIE assets	$ 1,335,915		$ 1,335,915		$ 1,374,802
Securitizations and Variable Interest Entities Textual [Abstract]
Carrying value of delinquent loans eligible for repurchase	551		551		1,200
Principal amount that would be payable to securitization vehicles	551		551		1,200
Equity Interests [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	11,200		11,200		11,000
Trust preferred securities [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	(2,100)		(2,100)		(2,000)
Trust preferred securities [Member] | Preferred Stock [Member]
Securitizations and Variable Interest Entities Textual [Abstract]
Carrying value - equity	2,500		2,500		2,500
Conforming Residential Mortgage Loan Securitization [Member]
Variable Interest Entity [Line Items]
Total VIE assets	1,132,124		1,132,124		1,172,833
Other/Nonconforming Residential Mortgage Loan Securitization [Member]
Variable Interest Entity [Line Items]
Total VIE assets	9,438		9,438		10,596
Commercial [Member]
Variable Interest Entity [Line Items]
Total VIE assets	154,690		154,690		153,350
Collateralized Debt Obligations Debt Securities [Member]
Variable Interest Entity [Line Items]
Total VIE assets	637		637		659
Asset-based finance structures [Member]
Variable Interest Entity [Line Items]
Total VIE assets	244		244		304
Tax Credit Structures [Member]
Variable Interest Entity [Line Items]
Total VIE assets	36,888		36,888		35,185
Collateralized loan obligations [Member]
Variable Interest Entity [Line Items]
Total VIE assets	176		176		2
Investment Funds [Member]
Variable Interest Entity [Line Items]
Total VIE assets	210		210		185
Other securitizations and transactions [Member]
Variable Interest Entity [Line Items]
Total VIE assets	1,508		1,508		1,688
VIEs that we do not consolidate [Member] | Waived fees [Member]
Securitizations and Variable Interest Entities Textual [Abstract]
Financial support provided to a nonconsolidated legal entity	10	$ 12	20	$ 25
Debt and equity interests [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	16,936		16,936		17,780
Maximum exposure to loss	16,936		16,936		17,780
Debt and equity interests [Member] | Conforming Residential Mortgage Loan Securitization [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	2,367		2,367		2,377
Maximum exposure to loss	2,367		2,367		2,377
Debt and equity interests [Member] | Other/Nonconforming Residential Mortgage Loan Securitization [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	37		37		453
Maximum exposure to loss	37		37		453
Debt and equity interests [Member] | Commercial [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	2,041		2,041		2,409
Maximum exposure to loss	2,041		2,041		2,409
Debt and equity interests [Member] | Collateralized Debt Obligations Debt Securities [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	0		0		0
Maximum exposure to loss	0		0		0
Debt and equity interests [Member] | Asset-based finance structures [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	143		143		205
Maximum exposure to loss	143		143		205
Debt and equity interests [Member] | Tax Credit Structures [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	12,232		12,232		12,087
Maximum exposure to loss	12,232		12,232		12,087
Debt and equity interests [Member] | Collateralized loan obligations [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	1		1		0
Maximum exposure to loss	1		1		0
Debt and equity interests [Member] | Investment Funds [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	49		49		42
Maximum exposure to loss	49		49		42
Debt and equity interests [Member] | Other securitizations and transactions [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	66		66		207
Maximum exposure to loss	66		66		207
Servicing assets [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	12,354		12,354		14,761
Maximum exposure to loss	12,354		12,354		14,761
Servicing assets [Member] | Conforming Residential Mortgage Loan Securitization [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	11,420		11,420		13,811
Maximum exposure to loss	11,420		11,420		13,811
Servicing assets [Member] | Other/Nonconforming Residential Mortgage Loan Securitization [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	57		57		57
Maximum exposure to loss	57		57		57
Servicing assets [Member] | Commercial [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	877		877		893
Maximum exposure to loss	877		877		893
Servicing assets [Member] | Collateralized Debt Obligations Debt Securities [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	0		0		0
Maximum exposure to loss	0		0		0
Servicing assets [Member] | Asset-based finance structures [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	0		0		0
Maximum exposure to loss	0		0		0
Servicing assets [Member] | Tax Credit Structures [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	0		0		0
Maximum exposure to loss	0		0		0
Servicing assets [Member] | Collateralized loan obligations [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	0		0		0
Maximum exposure to loss	0		0		0
Servicing assets [Member] | Investment Funds [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	0		0		0
Maximum exposure to loss	0		0		0
Servicing assets [Member] | Other securitizations and transactions [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	0		0		0
Maximum exposure to loss	0		0		0
Derivative [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	142		142		27
Maximum exposure to loss	143		143		78
Derivative [Member] | Conforming Residential Mortgage Loan Securitization [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	0		0		0
Maximum exposure to loss	0		0		0
Derivative [Member] | Other/Nonconforming Residential Mortgage Loan Securitization [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	0		0		0
Maximum exposure to loss	0		0		0
Derivative [Member] | Commercial [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	85		85		(22)
Maximum exposure to loss	85		85		28
Derivative [Member] | Collateralized Debt Obligations Debt Securities [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	4		4		5
Maximum exposure to loss	4		4		5
Derivative [Member] | Asset-based finance structures [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	0		0		0
Maximum exposure to loss	0		0		0
Derivative [Member] | Tax Credit Structures [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	0		0		0
Maximum exposure to loss	0		0		0
Derivative [Member] | Collateralized loan obligations [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	0		0		0
Maximum exposure to loss	0		0		0
Derivative [Member] | Investment Funds [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	0		0		0
Maximum exposure to loss	0		0		0
Derivative [Member] | Other securitizations and transactions [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	53		53		44
Maximum exposure to loss	54		54		45
Other commitments and guarantees [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	(4,055)		(4,055)		(4,101)
Maximum exposure to loss	14,532		14,532		14,415
Other commitments and guarantees [Member] | Conforming Residential Mortgage Loan Securitization [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	(136)		(136)		(171)
Maximum exposure to loss	902		902		1,183
Other commitments and guarantees [Member] | Other/Nonconforming Residential Mortgage Loan Securitization [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	0		0		0
Maximum exposure to loss	0		0		0
Other commitments and guarantees [Member] | Commercial [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	(42)		(42)		(40)
Maximum exposure to loss	12,007		12,007		11,563
Other commitments and guarantees [Member] | Collateralized Debt Obligations Debt Securities [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	(20)		(20)		(20)
Maximum exposure to loss	20		20		20
Other commitments and guarantees [Member] | Asset-based finance structures [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	0		0		0
Maximum exposure to loss	71		71		71
Other commitments and guarantees [Member] | Tax Credit Structures [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	(3,857)		(3,857)		(3,870)
Maximum exposure to loss	1,373		1,373		1,420
Other commitments and guarantees [Member] | Collateralized loan obligations [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	0		0		0
Maximum exposure to loss	0		0		0
Other commitments and guarantees [Member] | Investment Funds [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	0		0		0
Maximum exposure to loss	0		0		0
Other commitments and guarantees [Member] | Other securitizations and transactions [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	0		0		0
Maximum exposure to loss	159		159		158
Total exposure [Member]
Variable Interest Entity [Line Items]
Maximum exposure to loss	43,965		43,965		47,034
Total exposure [Member] | Conforming Residential Mortgage Loan Securitization [Member]
Variable Interest Entity [Line Items]
Maximum exposure to loss	14,689		14,689		17,371
Total exposure [Member] | Other/Nonconforming Residential Mortgage Loan Securitization [Member]
Variable Interest Entity [Line Items]
Maximum exposure to loss	94		94		510
Total exposure [Member] | Commercial [Member]
Variable Interest Entity [Line Items]
Maximum exposure to loss	15,010		15,010		14,893
Total exposure [Member] | Collateralized Debt Obligations Debt Securities [Member]
Variable Interest Entity [Line Items]
Maximum exposure to loss	24		24		25
Total exposure [Member] | Asset-based finance structures [Member]
Variable Interest Entity [Line Items]
Maximum exposure to loss	214		214		276
Total exposure [Member] | Tax Credit Structures [Member]
Variable Interest Entity [Line Items]
Maximum exposure to loss	13,605		13,605		13,507
Total exposure [Member] | Collateralized loan obligations [Member]
Variable Interest Entity [Line Items]
Maximum exposure to loss	1		1		0
Total exposure [Member] | Investment Funds [Member]
Variable Interest Entity [Line Items]
Maximum exposure to loss	49		49		42
Total exposure [Member] | Other securitizations and transactions [Member]
Variable Interest Entity [Line Items]
Maximum exposure to loss	279		279		410
Net assets [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	25,377		25,377		28,467
Net assets [Member] | Conforming Residential Mortgage Loan Securitization [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	13,651		13,651		16,017
Net assets [Member] | Other/Nonconforming Residential Mortgage Loan Securitization [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	94		94		510
Net assets [Member] | Commercial [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	2,961		2,961		3,240
Net assets [Member] | Collateralized Debt Obligations Debt Securities [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	(16)		(16)		(15)
Net assets [Member] | Asset-based finance structures [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	143		143		205
Net assets [Member] | Tax Credit Structures [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	8,375		8,375		8,217
Net assets [Member] | Collateralized loan obligations [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	1		1		0
Net assets [Member] | Investment Funds [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	49		49		42
Net assets [Member] | Other securitizations and transactions [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	$ 119		$ 119		$ 251