Commitments, Off-Balance Sheet Arrangements, Legal Proceedings and Regulatory Matters (Details Textuals) - USD ($)	3 Months Ended		6 Months Ended		9 Months Ended	12 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Sep. 30, 2020	Dec. 31, 2020	Dec. 31, 2019
Commitments, Off-Balance Sheet Arrangements, and Contingent Liabilities (Textuals) [Line Items]
Off-Balance Sheet, Credit Loss, Liability	$ 45,276,000		$ 45,276,000			$ 47,776,000	$ 21,907,000
Provision for credit losses			(2,500,000)			7,000,000
Expense Related to Qualified Affordable Housing Projects	8,000,000	$ 6,000,000	16,000,000	$ 12,000,000
Remaining Investment in Qualified Affordable Housing Projects	269,000,000		269,000,000			268,000,000
Variable Interest Entity Reporting Entity Involvement Unfunded Obligation Amount	97,000,000		97,000,000			118,000,000
Qualified Affordable Housing Investments, Impairment Loss			0		$ 0
Loans Repurchased Under Make Whole Requests	4,000,000		$ 4,000,000			$ 10,000,000
Loans Sold To Outside Investors Loss ReimbursementSettlement Paid			114			no
Loans Sold To Outside Investors Original Amount	15,300,000,000		$ 15,300,000,000
Loans Sold To Outside Investors Remaining Outstanding Amount	6,400,000,000		6,400,000,000
Mortgage Repurchase Reserve	1,000,000		1,000,000			$ 2,000,000
Residential Mortgage Loans Sold With Recourse Risk	24,000,000		24,000,000			36,000,000
Residential Mortgage Loans Sold With Credit Recourse Risk	29,000,000		29,000,000			33,000,000
UnconsolidatedProjectsLowIncomeHousing [Member]
Commitments, Off-Balance Sheet Arrangements, and Contingent Liabilities (Textuals) [Line Items]
Other Investments	271,000,000		271,000,000			272,000,000
PrincipalInvestmentCommitment [Member]
Commitments, Off-Balance Sheet Arrangements, and Contingent Liabilities (Textuals) [Line Items]
Other Investments	$ 23,000,000		$ 23,000,000			$ 25,000,000