Netting Arrangements for Certain Financial Instruments and Securities Financing Activities - Additional Information (Detail) $ in Billions	Jun. 30, 2019 USD ($)
Derivative [Line Items]
Notional amount of derivative	$ 520.3
Over the Counter Trades [Member]
Derivative [Line Items]
Notional amount of derivative	257.2
Exchange Cleared [Member]
Derivative [Line Items]
Notional amount of derivative	243.3
Exchange Traded [Member]
Derivative [Line Items]
Notional amount of derivative	$ 19.8