Annual report pursuant to Section 13 and 15(d)

Fair Value Measurements - Level 3 Reconciliation, Narrative (Details)

v3.10.0.1
Fair Value Measurements - Level 3 Reconciliation, Narrative (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]      
Gross Transfers out of Level 3 $ (504) $ 99 $ 362
Long-term debt      
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]      
Gross Transfers into Level 3 262 711 939
Gross Transfers out of Level 3 847 218 465
Federal funds purchased and securities loaned or sold under agreements to repurchase      
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]      
Gross Transfers into Level 3   58 19
Gross Transfers out of Level 3   263 1
Trading account assets      
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]      
Gross Transfers into Level 3 1,704 1,164 956
Gross Transfers out of Level 3 969 1,333 1,051
Loans held-for-sale      
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]      
Gross Transfers into Level 3 23 501 173
Gross Transfers out of Level 3 60 32 106
Available-for-sale Securities      
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]      
Gross Transfers into Level 3 838 69 16
Gross Transfers out of Level 3 1,070 139 117
Loans and leases      
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]      
Gross Transfers into Level 3 0 0 6
Gross Transfers out of Level 3 0 7 234
Other debt securities      
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]      
Gross Transfers into Level 3 365 0 0
Gross Transfers out of Level 3 $ 133 $ 0 $ 0