Investments in Limited Partnerships (Details) $ in Millions	12 Months Ended
	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)
Summary of Investment Holdings [Line Items]
Number of Investments in Affordable Housing Partnerships	16	15
Investments in Affordable Housing Partnerships Carrying Value, Net	$ 20.4	$ 22.8
Federal Affordable Housing Tax Credits	22.1
Expected Amortization of Investments in Affordable Housing Partnerships	20.4
Usage of Federal Affordable Housing Tax Credits	6.6	8.0	$ 6.6
Actual Amortization of Investments in Affordable Housing Partnerships	$ 5.5	$ 5.8	$ 5.0
For the First three years
Summary of Investment Holdings [Line Items]
Percentage of investments on credit allowance period	5.00%
For the next four years
Summary of Investment Holdings [Line Items]
Percentage of investments on credit allowance period	6.00%