Investment Portfolio - Available for Sale Investments (Substantially Restricted) (Details) - USD ($) $ in Millions	Mar. 31, 2023	Dec. 31, 2022
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	$ 1.4	$ 1.5
Gross Unrealized Gains	1.3	1.5
Fair Value	2.7	3.0
Asset-backed and other securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	0.0	0.0
Gross Unrealized Gains	1.3	1.5
Fair Value	1.3	1.5
Residential Mortgage Backed Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	1.4	1.5
Gross Unrealized Gains	0.0	0.0
Fair Value	$ 1.4	$ 1.5