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Income Taxes (Details) - USD ($)	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Income Tax Contingency [Line Items]
Total income tax expense (benefit), rate	19.40%	13.40%
Combined federal and state statutory tax rate	23.70%
Valuation allowance	$ 0		$ 0
Accrued Liabilities and Other Liabilities
Income Tax Contingency [Line Items]
Net deferred tax liability	11,000,000		$ 100,000,000
Key Corp
Income Tax Contingency [Line Items]
Unrecognized tax benefits	56,000,000
First Niagara Bank, N.A.
Income Tax Contingency [Line Items]
Allocated bad debt deductions	$ 92,000,000

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- Definition

Effective income tax rate reconciliation federal and state.

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Amount, after deferred tax asset, of deferred tax liability attributable to taxable differences with jurisdictional netting.

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-Publisher FASB
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Amount of deferred tax assets for which it is more likely than not that a tax benefit will not be realized.

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Amount of deferred tax liability not recognized because of the exceptions to comprehensive recognition of deferred taxes related to bad debt reserve for tax purposes of a qualified lender.

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Percentage of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

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Amount of unrecognized tax benefits.

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