Derivative Financial Instruments Cash flow hedges (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Derivative [Line Items]
Reclassifications into Interest expense on cash flow hedge	$ 766,000,000	$ 732,000,000	$ 2,300,000	$ 1,200,000
Federal Home Loan Bank 90-day Advances
Derivative [Line Items]
Derivative, Notional Amount	50,000,000		50,000,000
Interest Rate Swap [Member]
Derivative [Line Items]
Interest rate swaps related to debt	150,000,000		150,000,000		$ 160,000,000
Derivative, Notional Amount	$ 150,000,000		$ 150,000,000		$ 160,000,000