Derivative Financial Instruments Cash flow hedges (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Derivative [Line Items]
Reclassifications into Interest expense on cash flow hedge	$ 796,000,000	$ 365,000,000	$ 1,600,000	$ 483,000,000
Federal Home Loan Bank Borrowings [Member]
Derivative [Line Items]
Derivative, Notional Amount	110,000,000.0		110,000,000.0
Brokered Certificate of Deposit [Member]
Derivative [Line Items]
Derivative, Notional Amount	50,000,000.0		50,000,000.0
Interest Rate Swap [Member]
Derivative [Line Items]
Interest rate swaps related to debt	160,000,000		160,000,000		$ 160,000,000
Derivative, Notional Amount	$ 160,000,000.0		$ 160,000,000.0		$ 160,000,000