Loans and Leases - Restrictions, Concentrations (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
Net loans and leases	$ 57,269	$ 30,861
Loans, net of unearned income	58,232	31,061
Loans, net of unearned income	58,232	31,061
Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans pledged to secure potential borrowings	7,800	5,200
Loans, net of unearned income	33,104
Loans, net of unearned income	33,104	20,051
Commercial \| C&I
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	33,104	20,051
Commercial \| C&I \| Loans to mortgage companies
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	$ 5,400
Percentage contributed	26.00%
Loans, net of unearned income	$ 5,404	4,411
Commercial \| C&I \| Finance And Insurance Companies
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	3,100
Commercial \| Loans to mortgage companies
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	5,404	4,411
Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	11,725	6,177
Consumer \| Consumer real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	11,725
Loans, net of unearned income	11,725	6,177
Asset Pledged as Collateral
Accounts, Notes, Loans and Financing Receivable [Line Items]
Net loans and leases	$ 38,600	$ 19,200

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Amount before allowance and after deduction of deferred interest and fees, unamortized costs and premiums and discounts from face amounts, of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Excludes loans and leases covered under loss sharing agreements.

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Carrying amount as of the balance sheet date of loans that have been pledged as collateral for borrowings. If the secured party has the right by contract or custom to sell or re-pledge the collateral, then the debtor reclassifies that asset and report that asset in its statement of financial position separately from other assets not so encumbered.

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Amount, before allowance for credit loss, of financing receivable.

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