Loans and Leases - Loans and Leases Classified by Primary Purpose (Details) - USD ($) $ in Millions		Sep. 30, 2024	Dec. 31, 2023
Loans and leases held for sale:
Loans held for sale		$ 612	$ 378
Portfolio loans and leases:
Total portfolio loans and leases	[1]	116,668	117,234
Commercial
Portfolio loans and leases:
Total portfolio loans and leases		71,130	72,746
Commercial | Commercial and industrial loans
Loans and leases held for sale:
Loans held for sale		14	41
Portfolio loans and leases:
Total portfolio loans and leases		50,916	53,270
Commercial | Commercial leases
Loans and leases held for sale:
Loans held for sale		2	3
Portfolio loans and leases:
Total portfolio loans and leases		2,873	2,579
Commercial | Commercial mortgage loans
Loans and leases held for sale:
Loans held for sale		34	0
Portfolio loans and leases:
Total portfolio loans and leases		11,394	11,276
Commercial | Commercial construction loans
Loans and leases held for sale:
Loans held for sale		50	0
Portfolio loans and leases:
Total portfolio loans and leases		5,947	5,621
Consumer
Portfolio loans and leases:
Total portfolio loans and leases		45,538	44,488
Consumer | Residential mortgage loans
Loans and leases held for sale:
Loans held for sale		512	334
Portfolio loans and leases:
Total portfolio loans and leases		17,166	17,026
Consumer | Home equity
Portfolio loans and leases:
Total portfolio loans and leases		4,074	3,916
Consumer | Indirect secured consumer loans
Portfolio loans and leases:
Total portfolio loans and leases		15,942	14,965
Consumer | Credit card
Portfolio loans and leases:
Total portfolio loans and leases		1,703	1,865
Consumer | Solar energy installation loans
Portfolio loans and leases:
Total portfolio loans and leases		4,078	3,728
Consumer | Other consumer loans
Portfolio loans and leases:
Total portfolio loans and leases		$ 2,575	$ 2,988

[1] Includes $50 and $55 of other short-term investments, $1,131 and $1,573 of portfolio loans and leases, $(21) and $(28) of ALLL, $8 and $10 of other assets, $13 and $14 of other liabilities and $1,008 and $1,409 of long-term debt from consolidated VIEs that are included in their respective captions above at September 30, 2024 and December 31, 2023, respectively. For further information, refer to Note 12.