Commitments, Off-Balance Sheet Arrangements, Legal Proceedings and Regulatory Matters, Summary of Lending Related and Other Commitments (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Schedule of lending-related and other commitments [Line Items]
Lending related commitments, fair value	$ 0	$ 0
Commitments to extend credit, excluding commitments to originate residential mortgage loans held for sale(a)(b)
Summary of lending-related and other commitments
Lending related commitments	8,909,815	8,720,293
Standby letters of credit(c)
Summary of lending-related and other commitments
Lending related commitments	8,119	7,599
Standby letters of credit(c)
Summary of lending-related and other commitments
Lending related commitments	272,376	255,904
Standby letters of credit, fair value	$ 3,000	$ 2,000