Commitments, Contingencies and Guarantees - Schedule of Commitments, Contingencies and Guarantees (Details) $ in Millions	Jun. 30, 2018 USD ($)
Commitments to extend credit
Commitment, Contingencies and Guarantees disclosures
Commitments	$ 34,157
Issued standby and commercial letters of credit
Commitment, Contingencies and Guarantees disclosures
Commitments	5,023
Commitments to enter into forward-starting resale agreements
Commitment, Contingencies and Guarantees disclosures
Commitments	1,302
Other commitments
Commitment, Contingencies and Guarantees disclosures
Commitments	$ 568