Credit Quality - Summary of the Credit Risk Profile of the Residential Mortgage and Consumer Portfolio Segments by Class (Details) - USD ($) $ in Millions	Jun. 30, 2019	Dec. 31, 2018
Total loans and leases	$ 109,091	$ 95,086
Residential Mortgage
Total loans and leases	16,585	15,325
Home Equity
Total loans and leases	6,325	6,402
Indirect secured consumer loans
Total loans and leases	10,403	8,976
Credit Card
Total loans and leases	2,436	2,470
Other consumer loans
Total loans and leases	2,580	2,342
Performing Financing Receivable
Total loans and leases	38,198	35,395
Performing Financing Receivable | Residential Mortgage | Residential Mortgage Loans
Total loans and leases	16,562	15,303
Performing Financing Receivable | Home Equity | Consumer Portfolio Segment
Total loans and leases	6,247	6,332
Performing Financing Receivable | Indirect secured consumer loans | Consumer Portfolio Segment
Total loans and leases	10,401	8,975
Performing Financing Receivable | Credit Card | Consumer Portfolio Segment
Total loans and leases	2,410	2,444
Performing Financing Receivable | Other consumer loans | Consumer Portfolio Segment
Total loans and leases	2,578	2,341
Nonperforming Financing Receivable
Total loans and leases	131	120
Nonperforming Financing Receivable | Residential Mortgage | Residential Mortgage Loans
Total loans and leases	23	22
Nonperforming Financing Receivable | Home Equity | Consumer Portfolio Segment
Total loans and leases	78	70
Nonperforming Financing Receivable | Indirect secured consumer loans | Consumer Portfolio Segment
Total loans and leases	2	1
Nonperforming Financing Receivable | Credit Card | Consumer Portfolio Segment
Total loans and leases	26	26
Nonperforming Financing Receivable | Other consumer loans | Consumer Portfolio Segment
Total loans and leases	$ 2	$ 1