Loans and Leases - Loans and Leases Classified by Primary Purpose (Details) - USD ($) $ in Millions		Mar. 31, 2021	Dec. 31, 2020
Loans and leases held for sale:
Loans and leases held for sale	[1]	$ 5,477	$ 4,741
Portfolio loans and leases:
Commercial and industrial loans		49,094	49,665
Commercial mortgage loans		10,481	10,602
Commercial construction loans		6,198	5,815
Commercial leases		3,255	2,915
Residential mortgage loans		15,776	15,928
Home equity		4,815	5,183
Indirect secured consumer loans		14,336	13,653
Credit card		1,810	2,007
Other consumer loans		3,090	3,014
Total portfolio loans and leases	[2],[3]	108,855	108,782
Residential mortgage loans
Loans and leases held for sale:
Loans and leases held for sale		5,397	4,465
Commercial
Portfolio loans and leases:
Total portfolio loans and leases		69,028	68,997
Commercial | Commercial and industrial loans
Loans and leases held for sale:
Loans and leases held for sale		71	230
Portfolio loans and leases:
Total portfolio loans and leases		49,094	49,665
Loans and leases related to SBA Paycheck Protection Program of CARES Act		5,400	4,800
Commercial | Commercial mortgage loans
Loans and leases held for sale:
Loans and leases held for sale		9	7
Commercial | Commercial leases
Loans and leases held for sale:
Loans and leases held for sale		0	39
Portfolio loans and leases:
Total portfolio loans and leases		3,255	2,915
Consumer
Portfolio loans and leases:
Total portfolio loans and leases		39,827	39,785
Consumer | Residential mortgage loans | GNMA loans
Portfolio loans and leases:
Total portfolio loans and leases		$ 37	$ 39

[1] Includes $1,801 and $1,481 of residential mortgage loans held for sale measured at fair value and $9 and $0 of commercial loans held for sale measured at fair value at March 31, 2021 and December 31, 2020, respectively.

[2] Includes $153 and $161 of residential mortgage loans measured at fair value at March 31, 2021 and December 31, 2020, respectively.

[3] Includes $54 and $55 of other short-term investments, $633 and $756 of portfolio loans and leases, $(5) and $(7) of ALLL, $4 and $5 of other assets, $1 and $2 of other liabilities, and $540 and $656 of long-term debt from consolidated VIEs that are included in their respective captions above at March 31, 2021 and December 31, 2020, respectively. For further information, refer to Note 11.