Loans & Leases - Loans and Leases Classified by Primary Purpose (Details) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Loans held for sale:
Loans and leases held for sale	$ 1,223	$ 607
Portfolio loans and leases:
Commercial and industrial loans	50,768	44,340
Commercial mortgage loans	10,822	6,974
Commercial construction loans	5,281	4,657
Commercial leases	3,495	3,600
Residential mortgage loans	16,675	15,504
Home equity	6,218	6,402
Indirect secured consumer loans	11,026	8,976
Credit card	2,467	2,470
Other consumer loans and leases	2,657	2,342
Portfolio loans and leases	109,409	95,265
Commercial Portfolio Segment
Portfolio loans and leases:
Portfolio loans and leases	70,366	59,571
Consumer Portfolio Segment
Portfolio loans and leases:
Portfolio loans and leases	39,043	35,694
Commercial and industrial loans
Loans held for sale:
Loans and leases held for sale	86	67
Commercial mortgage loans
Loans held for sale:
Loans and leases held for sale	0	3
Residential mortgage loans
Loans held for sale:
Loans and leases held for sale	$ 1,137	$ 537