Securitizations and Variable Interest Entities, Unconsolidated VIEs (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
Variable Interest Entity [Line Items]
Total VIE assets	$ 1,371,938		$ 1,371,938		$ 1,395,604
Securitizations and Variable Interest Entities Textual [Abstract]
Carrying value of delinquent loans eligible for repurchase	$ 1,100		$ 1,100		$ 1,200
Percentage of underlying collateral rated as investment grade	100.00%		100.00%		100.00%
Principal amount that would be payable to securitization vehicles	$ 1,100		$ 1,100		$ 1,200
Conforming Residential Mortgage Loan Securitization [Member]
Variable Interest Entity [Line Items]
Total VIE assets	1,171,325		1,171,325		1,166,296
Other/Nonconforming Residential Mortgage Loan Securitization [Member]
Variable Interest Entity [Line Items]
Total VIE assets	16,198		16,198		18,805
Commercial Mortgage Backed Securities [Member]
Variable Interest Entity [Line Items]
Total VIE assets	144,257		144,257		166,596
Collateralized Debt Obligations Debt Securities [Member]
Variable Interest Entity [Line Items]
Total VIE assets	1,157		1,157		1,472
Collateralized Debt Obligations Loans [Member]
Variable Interest Entity [Line Items]
Total VIE assets	1,511		1,511		1,545
Asset-based finance structures [Member]
Variable Interest Entity [Line Items]
Total VIE assets	4,862		4,862		9,152
Tax Credit Structures [Member]
Variable Interest Entity [Line Items]
Total VIE assets	29,774		29,774		29,713
Collateralized Loan Obligations [Member]
Variable Interest Entity [Line Items]
Total VIE assets	29		29		78
Investment Funds [Member]
Variable Interest Entity [Line Items]
Total VIE assets	214		214		214
Other securitizations and transactions [Member]
Variable Interest Entity [Line Items]
Total VIE assets	2,611		2,611		1,733
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	13	$ 26	27	$ 56
Debt and equity interests [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	22,353		22,353		27,543
Maximum exposure to loss	22,353		22,353		27,543
Debt and equity interests [Member] | Conforming Residential Mortgage Loan Securitization [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	2,299		2,299		3,026
Maximum exposure to loss	2,299		2,299		3,026
Debt and equity interests [Member] | Other/Nonconforming Residential Mortgage Loan Securitization [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	801		801		873
Maximum exposure to loss	801		801		873
Debt and equity interests [Member] | Commercial Mortgage Backed Securities [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	2,556		2,556		4,258
Maximum exposure to loss	2,556		2,556		4,258
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] | Collateralized Debt Obligations Loans [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	1,473		1,473		1,507
Maximum exposure to loss	1,473		1,473		1,507
Debt and equity interests [Member] | Asset-based finance structures [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	3,755		3,755		6,522
Maximum exposure to loss	3,755		3,755		6,522
Debt and equity interests [Member] | Tax Credit Structures [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	10,811		10,811		10,669
Maximum exposure to loss	10,811		10,811		10,669
Debt and equity interests [Member] | Collateralized Loan Obligations [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	8		8		10
Maximum exposure to loss	8		8		10
Debt and equity interests [Member] | Investment Funds [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	54		54		48
Maximum exposure to loss	54		54		48
Debt and equity interests [Member] | Other securitizations and transactions [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	596		596		630
Maximum exposure to loss	596		596		630
Servicing assets [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	13,337		13,337		13,386
Maximum exposure to loss	13,337		13,337		13,386
Servicing assets [Member] | Conforming Residential Mortgage Loan Securitization [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	12,394		12,394		12,434
Maximum exposure to loss	12,394		12,394		12,434
Servicing assets [Member] | Other/Nonconforming Residential Mortgage Loan Securitization [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	90		90		109
Maximum exposure to loss	90		90		109
Servicing assets [Member] | Commercial Mortgage Backed Securities [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	853		853		843
Maximum exposure to loss	853		853		843
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] | Collateralized Debt Obligations Loans [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)	(15)		(15)		31
Maximum exposure to loss	186		186		187
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 Mortgage Backed Securities [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	75		75		87
Maximum exposure to loss	79		79		94
Derivative [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
Derivative [Member] | Collateralized Debt Obligations Loans [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	0		0		0
Maximum exposure to loss	0		0		0
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)	(90)		(90)		(56)
Maximum exposure to loss	107		107		93
Other commitments and guarantees [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	(3,517)		(3,517)		(3,903)
Maximum exposure to loss	11,917		11,917		11,748
Other commitments and guarantees [Member] | Conforming Residential Mortgage Loan Securitization [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	(180)		(180)		(232)
Maximum exposure to loss	875		875		979
Other commitments and guarantees [Member] | Other/Nonconforming Residential Mortgage Loan Securitization [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	(2)		(2)		(2)
Maximum exposure to loss	2		2		2
Other commitments and guarantees [Member] | Commercial Mortgage Backed Securities [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	(33)		(33)		(35)
Maximum exposure to loss	9,767		9,767		9,566
Other commitments and guarantees [Member] | Collateralized Debt Obligations Debt Securities [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	(20)		(20)		(25)
Maximum exposure to loss	20		20		25
Other commitments and guarantees [Member] | Collateralized Debt Obligations Loans [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] | Asset-based finance structures [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	0		0		0
Maximum exposure to loss	71		71		72
Other commitments and guarantees [Member] | Tax Credit Structures [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	(3,282)		(3,282)		(3,609)
Maximum exposure to loss	1,024		1,024		1,104
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	158		158		0
Total exposure [Member]
Variable Interest Entity [Line Items]
Maximum exposure to loss	47,793		47,793		52,864
Total exposure [Member] | Conforming Residential Mortgage Loan Securitization [Member]
Variable Interest Entity [Line Items]
Maximum exposure to loss	15,568		15,568		16,439
Total exposure [Member] | Other/Nonconforming Residential Mortgage Loan Securitization [Member]
Variable Interest Entity [Line Items]
Maximum exposure to loss	893		893		984
Total exposure [Member] | Commercial Mortgage Backed Securities [Member]
Variable Interest Entity [Line Items]
Maximum exposure to loss	13,255		13,255		14,761
Total exposure [Member] | Collateralized Debt Obligations Debt Securities [Member]
Variable Interest Entity [Line Items]
Maximum exposure to loss	20		20		25
Total exposure [Member] | Collateralized Debt Obligations Loans [Member]
Variable Interest Entity [Line Items]
Maximum exposure to loss	1,473		1,473		1,507
Total exposure [Member] | Asset-based finance structures [Member]
Variable Interest Entity [Line Items]
Maximum exposure to loss	3,826		3,826		6,594
Total exposure [Member] | Tax Credit Structures [Member]
Variable Interest Entity [Line Items]
Maximum exposure to loss	11,835		11,835		11,773
Total exposure [Member] | Collateralized Loan Obligations [Member]
Variable Interest Entity [Line Items]
Maximum exposure to loss	8		8		10
Total exposure [Member] | Investment Funds [Member]
Variable Interest Entity [Line Items]
Maximum exposure to loss	54		54		48
Total exposure [Member] | Other securitizations and transactions [Member]
Variable Interest Entity [Line Items]
Maximum exposure to loss	861		861		723
Net assets [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	32,158		32,158		37,057
Net assets [Member] | Conforming Residential Mortgage Loan Securitization [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	14,513		14,513		15,228
Net assets [Member] | Other/Nonconforming Residential Mortgage Loan Securitization [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	889		889		980
Net assets [Member] | Commercial Mortgage Backed Securities [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	3,451		3,451		5,153
Net assets [Member] | Collateralized Debt Obligations Debt Securities [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	(20)		(20)		(25)
Net assets [Member] | Collateralized Debt Obligations Loans [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	1,473		1,473		1,507
Net assets [Member] | Asset-based finance structures [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	3,755		3,755		6,522
Net assets [Member] | Tax Credit Structures [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	7,529		7,529		7,060
Net assets [Member] | Collateralized Loan Obligations [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	8		8		10
Net assets [Member] | Investment Funds [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	54		54		48
Net assets [Member] | Other securitizations and transactions [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	506		506		574
Equity Interests [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	10,300		10,300		10,300
Other investments [Member]
Securitizations and Variable Interest Entities Textual [Abstract]
Securities available for sale portfolio of ARS issued by VIEs	420		420		453
Trust preferred securities [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	(2,000)		(2,000)		(2,100)
Securitizations and Variable Interest Entities Textual [Abstract]
Trust preferred securities redeemed			150
Trust preferred securities [Member] | Preferred Stock [Member]
Securitizations and Variable Interest Entities Textual [Abstract]
Carrying value - equity	$ 2,500		$ 2,500		$ 2,500