Restricted Securities Available For Sale (Schedule Of Restricted Securities Available For Sale By Aging Category) (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	$ 11.1	$ 40.0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	42.3	26.9
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	0.1	1.5
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	1.9	2.3
Debt Securities, Available-for-sale, Unrealized Loss Position	53.4	66.9
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	2.0	3.8
Corporate bonds [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	2.7	15.1
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	18.4	13.3
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	0.0	0.6
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	0.9	1.1
Debt Securities, Available-for-sale, Unrealized Loss Position	21.1	28.4
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	0.9	1.7
US Government and agency securities [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	6.8	18.0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	16.4	9.2
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	0.1	0.8
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	0.8	0.9
Debt Securities, Available-for-sale, Unrealized Loss Position	23.2	27.2
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	0.9	1.7
Asset-backed Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	1.6	6.6
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	7.3	4.4
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	0.0	0.1
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	0.2	0.3
Debt Securities, Available-for-sale, Unrealized Loss Position	8.9	11.0
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	0.2	0.4
Mortgage-backed securities [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	0.0	0.3
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	0.2	0.0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	0.0	0.0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	0.0	0.0
Debt Securities, Available-for-sale, Unrealized Loss Position	0.2	0.3
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	$ 0.0	$ 0.0