Annual report pursuant to Section 13 and 15(d)

Securitizations and Other Variable Interest Entities - Other Asset-backed Securitizations, Additional Information (Details)

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Securitizations and Other Variable Interest Entities - Other Asset-backed Securitizations, Additional Information (Details) - USD ($)
 12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Home equity lines of credit      
Variable Interest Entity [Line Items]      
Assets of deconsolidated securitization vehicles $ 0 $ 0 $ 488,000,000
Liabilities of deconsolidated securitization vehicles 0 0 611,000,000
Gain (loss) on deconsolidation     123,000,000
Credit Card Receivable      
Variable Interest Entity [Line Items]      
Principal balance outstanding $ 7,400,000,000 7,500,000,000  
Transferred financial assets, stated interest rate 0.00%    
Credit Card Receivable | Senior Lien      
Variable Interest Entity [Line Items]      
Transferred financial assets, amount issued $ 3,100,000,000 750,000,000 2,300,000,000
Credit Card Receivable | Junior Lien      
Variable Interest Entity [Line Items]      
Transferred financial assets, amount issued 500,000,000 121,000,000 371,000,000
Resecuritization Trusts      
Variable Interest Entity [Line Items]      
Cash proceeds from new securitizations 25,100,000,000 23,400,000,000 30,700,000,000
Resecuritization Trusts | Debt securities      
Variable Interest Entity [Line Items]      
Cash proceeds from new securitizations $ 3,300,000,000 3,300,000,000 9,800,000,000
Resecuritization Trusts | Held-to-maturity Securities      
Variable Interest Entity [Line Items]      
Cash proceeds from new securitizations     $ 6,900,000,000
Municipal Bond Trusts | Unconsolidated VIEs      
Variable Interest Entity [Line Items]      
Liquidity commitments to unconsolidated securitization trusts   $ 1,600,000,000  
Weighted average remaining life of bonds held in the trusts in years 6 years