Loans and Leases - Summary of Financial Effects of Troubled Debt Restructurings (Details) $ in Millions	3 Months Ended	6 Months Ended
	Jun. 30, 2020 USD ($) Investment	Jun. 30, 2021 USD ($) Investment	Jun. 30, 2020 USD ($) Investment
Financing Receivable Modifications [Line Items]
Number of loans classified as a non-accrual TDRs | Investment	12		20
Pre-Modification Recorded Investment	$ 17		$ 19
Post-Modification Recorded Investment	$ 16		$ 18
Weighted Average Interest Rate, Pre-Modification	7.28%		6.89%
Weighted Average Interest Rate, Post-Modification	3.45%		3.42%
Trouble debt restructuring, charge-off amount	$ 1		$ 1
Commercial and Industrial
Financing Receivable Modifications [Line Items]
Number of loans classified as a non-accrual TDRs | Investment	11		19
Pre-Modification Recorded Investment	$ 2		$ 4
Post-Modification Recorded Investment	$ 1		$ 3
Weighted Average Interest Rate, Pre-Modification	2.92%		3.08%
Weighted Average Interest Rate, Post-Modification	2.92%		3.03%
Trouble debt restructuring, charge-off amount	$ 1		$ 1
Commercial Real Estate
Financing Receivable Modifications [Line Items]
Number of loans classified as a non-accrual TDRs | Investment	1		1
Pre-Modification Recorded Investment	$ 15		$ 15
Post-Modification Recorded Investment	$ 15		$ 15
Weighted Average Interest Rate, Pre-Modification	8.00%		8.00%
Weighted Average Interest Rate, Post-Modification	3.50%		3.50%
Multi-Family
Financing Receivable Modifications [Line Items]
Number of loans classified as a non-accrual TDRs | Investment		1
Pre-Modification Recorded Investment		$ 7
Post-Modification Recorded Investment		$ 7
Weighted Average Interest Rate, Pre-Modification		3.13%
Weighted Average Interest Rate, Post-Modification		3.25%