Securitizations and Variable Interest Entities, Significant Continuing Involvement - Unconsolidated VIEs (Details) - USD ($) $ in Millions	Jun. 30, 2015	Dec. 31, 2014
Variable Interest Entity [Line Items]
Total VIE assets	$ 1,508,927	$ 1,566,049
Conforming Residential Mortgage Loan Securitization [Member]
Variable Interest Entity [Line Items]
Total VIE assets	1,223,715	1,268,200
Other/Nonconforming Residential Mortgage Loan Securitization [Member]
Variable Interest Entity [Line Items]
Total VIE assets	28,487	32,213
Commercial Mortgage Backed Securities [Member]
Variable Interest Entity [Line Items]
Total VIE assets	191,038	196,510
Collateralized Debt Obligations Debt Securities [Member]
Variable Interest Entity [Line Items]
Total VIE assets	4,285	5,039
Collateralized Debt Obligations Loans [Member]
Variable Interest Entity [Line Items]
Total VIE assets	4,253	5,347
Asset-based finance structures [Member]
Variable Interest Entity [Line Items]
Total VIE assets	16,040	18,954
Tax Credit Structures [Member]
Variable Interest Entity [Line Items]
Total VIE assets	24,405	22,859
Collateralized Loan Obligations [Member]
Variable Interest Entity [Line Items]
Total VIE assets	1,619	1,251
Investment Funds [Member]
Variable Interest Entity [Line Items]
Total VIE assets	1,730	2,764
Other securitizations and transactions [Member]
Variable Interest Entity [Line Items]
Total VIE assets	13,355	12,912
Debt and equity interests [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	35,683	40,645
Maximum exposure to loss	35,683	40,645
Debt and equity interests [Member] | Conforming Residential Mortgage Loan Securitization [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	2,824	2,846
Maximum exposure to loss	2,824	2,846
Debt and equity interests [Member] | Other/Nonconforming Residential Mortgage Loan Securitization [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	1,465	1,644
Maximum exposure to loss	1,465	1,644
Debt and equity interests [Member] | Commercial Mortgage Backed Securities [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	7,238	8,756
Maximum exposure to loss	7,238	8,756
Debt and equity interests [Member] | Collateralized Debt Obligations Debt Securities [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	4	11
Maximum exposure to loss	4	11
Debt and equity interests [Member] | Collateralized Debt Obligations Loans [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	4,146	5,221
Maximum exposure to loss	4,146	5,221
Debt and equity interests [Member] | Asset-based finance structures [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	10,345	13,044
Maximum exposure to loss	10,345	13,044
Debt and equity interests [Member] | Tax Credit Structures [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	8,461	7,809
Maximum exposure to loss	8,461	7,809
Debt and equity interests [Member] | Collateralized Loan Obligations [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	478	518
Maximum exposure to loss	478	518
Debt and equity interests [Member] | Investment Funds [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	48	49
Maximum exposure to loss	48	49
Debt and equity interests [Member] | Other securitizations and transactions [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	674	747
Maximum exposure to loss	674	747
Servicing assets [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	12,648	12,562
Maximum exposure to loss	12,648	12,562
Servicing assets [Member] | Conforming Residential Mortgage Loan Securitization [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	11,786	11,684
Maximum exposure to loss	11,786	11,684
Servicing assets [Member] | Other/Nonconforming Residential Mortgage Loan Securitization [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	167	209
Maximum exposure to loss	167	209
Servicing assets [Member] | Commercial Mortgage Backed Securities [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	678	650
Maximum exposure to loss	678	650
Servicing assets [Member] | Collateralized Debt Obligations Debt Securities [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	0	0
Maximum exposure to loss	0	0
Servicing assets [Member] | Collateralized Debt Obligations Loans [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	0	0
Maximum exposure to loss	0	0
Servicing assets [Member] | Asset-based finance structures [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	0	0
Maximum exposure to loss	0	0
Servicing assets [Member] | Tax Credit Structures [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	0	0
Maximum exposure to loss	0	0
Servicing assets [Member] | Collateralized Loan Obligations [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	0	0
Maximum exposure to loss	0	0
Servicing assets [Member] | Investment Funds [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	0	0
Maximum exposure to loss	0	0
Servicing assets [Member] | Other securitizations and transactions [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	17	19
Maximum exposure to loss	17	19
Derivative [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	218	325
Maximum exposure to loss	555	653
Derivative [Member] | Conforming Residential Mortgage Loan Securitization [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	0	0
Maximum exposure to loss	0	0
Derivative [Member] | Other/Nonconforming Residential Mortgage Loan Securitization [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	0	0
Maximum exposure to loss	0	0
Derivative [Member] | Commercial Mortgage Backed Securities [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	195	251
Maximum exposure to loss	195	251
Derivative [Member] | Collateralized Debt Obligations Debt Securities [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	135	163
Maximum exposure to loss	135	163
Derivative [Member] | Collateralized Debt Obligations Loans [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	0	0
Maximum exposure to loss	0	0
Derivative [Member] | Asset-based finance structures [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	(68)	(71)
Maximum exposure to loss	83	89
Derivative [Member] | Tax Credit Structures [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	0	0
Maximum exposure to loss	0	0
Derivative [Member] | Collateralized Loan Obligations [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	0	0
Maximum exposure to loss	0	0
Derivative [Member] | Investment Funds [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	0	0
Maximum exposure to loss	0	0
Derivative [Member] | Other securitizations and transactions [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	(44)	(18)
Maximum exposure to loss	142	150
Other commitments and guarantees [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	(3,575)	(3,316)
Maximum exposure to loss	10,484	10,247
Other commitments and guarantees [Member] | Conforming Residential Mortgage Loan Securitization [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	(557)	(581)
Maximum exposure to loss	2,083	2,507
Other commitments and guarantees [Member] | Other/Nonconforming Residential Mortgage Loan Securitization [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	(5)	(8)
Maximum exposure to loss	348	345
Other commitments and guarantees [Member] | Commercial Mortgage Backed Securities [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	(25)	(32)
Maximum exposure to loss	6,537	5,715
Other commitments and guarantees [Member] | Collateralized Debt Obligations Debt Securities [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	(91)	(105)
Maximum exposure to loss	91	105
Other commitments and guarantees [Member] | Collateralized Debt Obligations Loans [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	0	0
Maximum exposure to loss	0	0
Other commitments and guarantees [Member] | Asset-based finance structures [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	0	0
Maximum exposure to loss	461	656
Other commitments and guarantees [Member] | Tax Credit Structures [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	(2,883)	(2,585)
Maximum exposure to loss	800	725
Other commitments and guarantees [Member] | Collateralized Loan Obligations [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	0	0
Maximum exposure to loss	0	38
Other commitments and guarantees [Member] | Investment Funds [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	0	0
Maximum exposure to loss	0	0
Other commitments and guarantees [Member] | Other securitizations and transactions [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	(14)	(5)
Maximum exposure to loss	164	156
Net assets [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	44,974	50,216
Net assets [Member] | Conforming Residential Mortgage Loan Securitization [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	14,053	13,949
Net assets [Member] | Other/Nonconforming Residential Mortgage Loan Securitization [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	1,627	1,845
Net assets [Member] | Commercial Mortgage Backed Securities [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	8,086	9,625
Net assets [Member] | Collateralized Debt Obligations Debt Securities [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	48	69
Net assets [Member] | Collateralized Debt Obligations Loans [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	4,146	5,221
Net assets [Member] | Asset-based finance structures [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	10,277	12,973
Net assets [Member] | Tax Credit Structures [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	5,578	5,224
Net assets [Member] | Collateralized Loan Obligations [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	478	518
Net assets [Member] | Investment Funds [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	48	49
Net assets [Member] | Other securitizations and transactions [Member]
Variable Interest Entity [Line Items]
Carrying value asset (liability)	633	743
Total exposure [Member]
Variable Interest Entity [Line Items]
Maximum exposure to loss	59,370	64,107
Total exposure [Member] | Conforming Residential Mortgage Loan Securitization [Member]
Variable Interest Entity [Line Items]
Maximum exposure to loss	16,693	17,037
Total exposure [Member] | Other/Nonconforming Residential Mortgage Loan Securitization [Member]
Variable Interest Entity [Line Items]
Maximum exposure to loss	1,980	2,198
Total exposure [Member] | Commercial Mortgage Backed Securities [Member]
Variable Interest Entity [Line Items]
Maximum exposure to loss	14,648	15,372
Total exposure [Member] | Collateralized Debt Obligations Debt Securities [Member]
Variable Interest Entity [Line Items]
Maximum exposure to loss	230	279
Total exposure [Member] | Collateralized Debt Obligations Loans [Member]
Variable Interest Entity [Line Items]
Maximum exposure to loss	4,146	5,221
Total exposure [Member] | Asset-based finance structures [Member]
Variable Interest Entity [Line Items]
Maximum exposure to loss	10,889	13,789
Total exposure [Member] | Tax Credit Structures [Member]
Variable Interest Entity [Line Items]
Maximum exposure to loss	9,261	8,534
Total exposure [Member] | Collateralized Loan Obligations [Member]
Variable Interest Entity [Line Items]
Maximum exposure to loss	478	556
Total exposure [Member] | Investment Funds [Member]
Variable Interest Entity [Line Items]
Maximum exposure to loss	48	49
Total exposure [Member] | Other securitizations and transactions [Member]
Variable Interest Entity [Line Items]
Maximum exposure to loss	$ 997	$ 1,072