Commitments, Off-Balance Sheet Arrangements, Legal Proceedings and Regulatory Matters (Details Textuals) - USD ($)	3 Months Ended	12 Months Ended
	Mar. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Commitments, Off-Balance Sheet Arrangements, and Contingent Liabilities (Textuals) [Line Items]
Off-Balance Sheet, Credit Loss, Liability	$ 38,776,000	$ 39,776,000	$ 47,776,000
Provision for credit losses	(1,000,000)	(8,000,000)
Expense Related to Qualified Affordable Housing Projects	8,000,000
Remaining Investment in Qualified Affordable Housing Projects	253,000,000	262,000,000
Variable Interest Entity Reporting Entity Involvement Unfunded Obligation Amount	69,000,000	80,000,000
Qualified Affordable Housing Investments, Impairment Loss	0	0
Loans Repurchased Under Make Whole Requests	$ 2,000,000	$ 8,000,000
Loans Sold To Outside Investors Loss ReimbursementSettlement Paid	no	114,000
Loans Sold To Outside Investors Original Amount	$ 7,200,000,000
Loans Sold To Outside Investors Remaining Outstanding Amount	4,600,000,000
Mortgage Repurchase Reserve	1,000,000
Residential Mortgage Loans Sold With Recourse Risk	8,000,000	$ 10,000,000
Residential Mortgage Loans Sold With Credit Recourse Risk	23,000,000	24,000,000
Residential Mortgage Loans with Credit Risk Recourse	0
UnconsolidatedProjectsLowIncomeHousing [Member]
Commitments, Off-Balance Sheet Arrangements, and Contingent Liabilities (Textuals) [Line Items]
Other Investments	259,000,000	$ 268,000,000
PrincipalInvestmentCommitment [Member]
Commitments, Off-Balance Sheet Arrangements, and Contingent Liabilities (Textuals) [Line Items]
Other Investments	$ 25,000,000