Derivatives - Credit-related Contingent Features and Collateral (Details) $ in Millions	Jun. 30, 2018 USD ($)
Derivative [Line Items]
Additional collateral required to be posted upon downgrade, one incremental notch	$ 643
Additional collateral required to be posted upon downgrade, second incremental notch	289
Credit derivatives
Derivative [Line Items]
Derivative liability subject to unilateral termination upon downgrade, one incremental notch	184
Derivative liability subject to unilateral termination upon downgrade, second incremental notch	614
Collateral posted subject to unilateral termination upon downgrade, one incremental notch	115
Collateral posted subject to unilateral termination upon downgrade, second incremental notch	479
Bank of America, N.A.
Derivative [Line Items]
Additional collateral required to be posted upon downgrade, one incremental notch	322
Additional collateral required to be posted upon downgrade, second incremental notch	$ 247