Pension And Other Postretirement Benefits Benefit Obligation (Schedule Of Net Funded Status) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance, beginning of year	$ 433.1
Balance, end of year	508.2	$ 433.1
Paid from Company assets for unfunded nonqualified benefits	3.9	2.0
Pension Benefits [Member]
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit obligation, beginning of period	577.9	841.9
Service cost	24.3	26.4	$ 30.2
Interest cost	31.9	25.5	23.9
Actuarial loss (gain)	36.8	(221.0)
Benefits paid from plan assets	(44.7)	(0.4)
Benefits paid from Company assets	(3.9)	(2.0)
Plan participants' contributions
Administrative expenses paid	(5.5)	(1.5)
Settlement charge		(91.0)
Benefit obligation, end of period	616.8	577.9	841.9
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance, beginning of year	433.1	680.7
Actual return on plan assets	25.3	(197.5)
Employer contributions	103.9	44.8
Plan participants' contributions
Benefits paid	(48.6)	(2.4)
Administrative expenses paid	(5.5)	(1.5)
Settlements		(91.0)
Balance, end of year	508.2	433.1	680.7
Unfunded status	108.6	144.8
Postretirement Benefits [Member]
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit obligation, beginning of period	62.3	75.1
Service cost	1.4	2.0	2.2
Interest cost	3.4	2.0	1.7
Actuarial loss (gain)		(12.0)
Benefits paid from plan assets
Benefits paid from Company assets	(4.8)	(5.3)
Plan participants' contributions	0.1	0.5
Administrative expenses paid
Settlement charge
Benefit obligation, end of period	62.4	62.3	75.1
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance, beginning of year
Actual return on plan assets
Employer contributions	4.7	4.8
Plan participants' contributions	0.1	0.5
Benefits paid	(4.8)	(5.3)
Administrative expenses paid
Settlements
Balance, end of year
Unfunded status	$ 62.4	$ 62.3