Loans and Leases - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended			6 Months Ended
	Jun. 30, 2020		Jun. 30, 2019	Jun. 30, 2020		Jun. 30, 2019	Mar. 31, 2020	Jan. 01, 2020	Dec. 31, 2019		Mar. 31, 2019	Dec. 31, 2018
Accounts, Notes, Loans and Financing Receivable
Unearned income	$ 309			$ 309					$ 354
Net premium	173			173					249
Accrued interest receivable	334			334
Loans pledged at the FHLB	15,500			15,500					16,700
Loans pledged at the FRB	37,700			37,700					47,300
Direct financing lease - interest income	17		$ 26	35		$ 48
Sales type lease - interest income	6		2	13		3
Allowance for loan and lease losses	2,696	[1]	$ 1,115	2,696	[1]	$ 1,115	$ 2,348	$ 33	1,202	[1]	$ 1,115	$ 1,103
Commercial Leases
Accounts, Notes, Loans and Financing Receivable
Allowance for loan and lease losses	$ 42			$ 42					$ 17

[1] Includes $66 and $74 of other short-term investments, $1,032 and $1,354 of portfolio loans and leases, $(14) and $(7) of ALLL, $7 and $8 of other assets, $2 and $2 of other liabilities, and $933 and $1,253 of long-term debt from consolidated VIEs that are included in their respective captions above at June 30, 2020 and December 31, 2019, respectively. For further information refer to Note 13.