Pension And Other Postretirement Benefits (Schedule Of Changes In Fair Value Of Plan Assets) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan fair value of plan assets measured at net asset value	$ 508.2	$ 433.1
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
Investments Measured at NAV [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan fair value of plan assets measured at net asset value	174.2	169.6
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance, beginning of year	169.6
Balance, end of year	174.2	169.6
Quoted Prices in Active Markets for Identical Inputs (Level 1) [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan fair value of plan assets measured at net asset value	48.3	43.0
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance, beginning of year	43.0
Balance, end of year	48.3	43.0
Significant Other Observable Inputs (Level 2) [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan fair value of plan assets measured at net asset value	252.1	185.5
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance, beginning of year	185.5
Balance, end of year	252.1	185.5
Significant Unobservable Inputs (Level 3) [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan fair value of plan assets measured at net asset value	33.6	35.0
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance, beginning of year	35.0	33.1
Realized gains	0.2	1.0
Unrealized gains	0.6	3.0
Purchases	0.1	0.3
Sales	(2.3)	(2.4)
Balance, end of year	33.6	35.0
Equity Securities - U.S. [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan fair value of plan assets measured at net asset value	30.1	28.3
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance, beginning of year	28.3
Balance, end of year	30.1	28.3
Equity Securities - U.S. [Member] | Quoted Prices in Active Markets for Identical Inputs (Level 1) [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan fair value of plan assets measured at net asset value	30.1	28.3
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance, beginning of year	28.3
Balance, end of year	30.1	28.3
Equity Securities - International [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan fair value of plan assets measured at net asset value	25.1	22.5
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance, beginning of year	22.5
Balance, end of year	25.1	22.5
Equity Securities - International [Member] | Investments Measured at NAV [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan fair value of plan assets measured at net asset value	20.0	9.1
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance, beginning of year	9.1
Balance, end of year	20.0	9.1
Equity Securities - International [Member] | Quoted Prices in Active Markets for Identical Inputs (Level 1) [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan fair value of plan assets measured at net asset value	5.1	13.4
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance, beginning of year	13.4
Balance, end of year	5.1	13.4
Fixed Income Investments - U.S. [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan fair value of plan assets measured at net asset value	265.0	198.2
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance, beginning of year	198.2
Balance, end of year	265.0	198.2
Fixed Income Investments - U.S. [Member] | Investments Measured at NAV [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan fair value of plan assets measured at net asset value	12.9	12.7
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance, beginning of year	12.7
Balance, end of year	12.9	12.7
Fixed Income Investments - U.S. [Member] | Significant Other Observable Inputs (Level 2) [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan fair value of plan assets measured at net asset value	252.1	185.5
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance, beginning of year	185.5
Balance, end of year	252.1	185.5
Hedge Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan fair value of plan assets measured at net asset value	7.5	27.4
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance, beginning of year	27.4
Balance, end of year	7.5	27.4
Hedge Funds [Member] | Investments Measured at NAV [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan fair value of plan assets measured at net asset value	7.5	27.4
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance, beginning of year	27.4
Balance, end of year	7.5	27.4
Real assets [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan fair value of plan assets measured at net asset value	28.0	21.5
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance, beginning of year	21.5
Balance, end of year	28.0	21.5
Real assets [Member] | Investments Measured at NAV [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan fair value of plan assets measured at net asset value	14.9	20.2
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance, beginning of year	20.2
Balance, end of year	14.9	20.2
Real assets [Member] | Quoted Prices in Active Markets for Identical Inputs (Level 1) [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan fair value of plan assets measured at net asset value	13.1	1.3
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance, beginning of year	1.3
Balance, end of year	13.1	1.3
Private equity [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan fair value of plan assets measured at net asset value	39.8	34.5
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance, beginning of year	34.5
Balance, end of year	39.8	34.5
Private equity [Member] | Investments Measured at NAV [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan fair value of plan assets measured at net asset value	17.6	10.9
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance, beginning of year	10.9
Balance, end of year	17.6	10.9
Private equity [Member] | Significant Unobservable Inputs (Level 3) [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan fair value of plan assets measured at net asset value	22.2	23.6
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance, beginning of year	23.6	21.7
Realized gains	0.2	0.8
Unrealized gains	(0.7)	2.3
Purchases	0.1	0.3
Sales	(1.0)	(1.5)
Balance, end of year	22.2	23.6
Other investments [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan fair value of plan assets measured at net asset value	19.5	16.8
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance, beginning of year	16.8
Balance, end of year	19.5	16.8
Other investments [Member] | Investments Measured at NAV [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan fair value of plan assets measured at net asset value	8.1	5.4
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance, beginning of year	5.4
Balance, end of year	8.1	5.4
Other investments [Member] | Significant Unobservable Inputs (Level 3) [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan fair value of plan assets measured at net asset value	11.4	11.4
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance, beginning of year	11.4	11.4
Realized gains		0.2
Unrealized gains	1.3	0.7
Purchases
Sales	(1.3)	(0.9)
Balance, end of year	11.4	11.4
Short-term Investments [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan fair value of plan assets measured at net asset value	93.2	83.9
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance, beginning of year	83.9
Balance, end of year	93.2	83.9
Short-term Investments [Member] | Investments Measured at NAV [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan fair value of plan assets measured at net asset value	93.2	83.9
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance, beginning of year	83.9
Balance, end of year	$ 93.2	$ 83.9