Pension And Other Postretirement Benefits (Schedule Of Changes In Fair Value Of Plan Assets) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan fair value of plan assets measured at net asset value	$ 433.1	$ 680.7
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance, beginning of year	680.7
Balance, end of year	433.1	680.7
Investments Measured at NAV [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan fair value of plan assets measured at net asset value	169.6	291.9
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance, beginning of year	291.9
Balance, end of year	169.6	291.9
Quoted Prices in Active Markets for Identical Inputs (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan fair value of plan assets measured at net asset value	43.0	76.0
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance, beginning of year	76.0
Balance, end of year	43.0	76.0
Significant Other Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan fair value of plan assets measured at net asset value	185.5	279.7
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance, beginning of year	279.7
Balance, end of year	185.5	279.7
Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan fair value of plan assets measured at net asset value	35.0	33.1
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance, beginning of year	33.1	25.2
Realized gains	1.0	1.0
Unrealized gains	3.0	10.3
Purchases	0.3	0.1
Sales	(2.4)	(3.5)
Balance, end of year	35.0	33.1
Equity Securities - U.S.
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan fair value of plan assets measured at net asset value	28.3	40.9
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance, beginning of year	40.9
Balance, end of year	28.3	40.9
Equity Securities - U.S. | Investments Measured at NAV [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan fair value of plan assets measured at net asset value		13.6
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance, beginning of year	13.6
Balance, end of year		13.6
Equity Securities - U.S. | Quoted Prices in Active Markets for Identical Inputs (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan fair value of plan assets measured at net asset value	28.3	27.3
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance, beginning of year	27.3
Balance, end of year	28.3	27.3
Equity Securities - International
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan fair value of plan assets measured at net asset value	22.5	42.3
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance, beginning of year	42.3
Balance, end of year	22.5	42.3
Equity Securities - International | Investments Measured at NAV [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan fair value of plan assets measured at net asset value	9.1	13.9
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance, beginning of year	13.9
Balance, end of year	9.1	13.9
Equity Securities - International | Quoted Prices in Active Markets for Identical Inputs (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan fair value of plan assets measured at net asset value	13.4	28.4
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance, beginning of year	28.4
Balance, end of year	13.4	28.4
Fixed Income Investments - U.S.
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan fair value of plan assets measured at net asset value	198.2	375.8
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance, beginning of year	375.8
Balance, end of year	198.2	375.8
Fixed Income Investments - U.S. | Investments Measured at NAV [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan fair value of plan assets measured at net asset value	12.7	96.1
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance, beginning of year	96.1
Balance, end of year	12.7	96.1
Fixed Income Investments - U.S. | Significant Other Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan fair value of plan assets measured at net asset value	185.5	279.7
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance, beginning of year	279.7
Balance, end of year	185.5	279.7
Hedge Funds
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan fair value of plan assets measured at net asset value	27.4	41.8
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance, beginning of year	41.8
Balance, end of year	27.4	41.8
Hedge Funds | Investments Measured at NAV [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan fair value of plan assets measured at net asset value	27.4	41.8
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance, beginning of year	41.8
Balance, end of year	27.4	41.8
Real assets
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan fair value of plan assets measured at net asset value	21.5	36.7
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance, beginning of year	36.7
Balance, end of year	21.5	36.7
Real assets | Investments Measured at NAV [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan fair value of plan assets measured at net asset value	20.2	16.4
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance, beginning of year	16.4
Balance, end of year	20.2	16.4
Real assets | Quoted Prices in Active Markets for Identical Inputs (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan fair value of plan assets measured at net asset value	1.3	20.3
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance, beginning of year	20.3
Balance, end of year	1.3	20.3
Private equity
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan fair value of plan assets measured at net asset value	34.5	29.9
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance, beginning of year	29.9
Balance, end of year	34.5	29.9
Private equity | Investments Measured at NAV [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan fair value of plan assets measured at net asset value	10.9	8.2
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance, beginning of year	8.2
Balance, end of year	10.9	8.2
Private equity | Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan fair value of plan assets measured at net asset value	23.6	21.7
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance, beginning of year	21.7	13.8
Realized gains	0.8	0.8
Unrealized gains	2.3	9.2
Purchases	0.3	0.1
Sales	(1.5)	(2.2)
Balance, end of year	23.6	21.7
Other
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan fair value of plan assets measured at net asset value	16.8	31.5
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance, beginning of year	31.5
Balance, end of year	16.8	31.5
Other | Investments Measured at NAV [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan fair value of plan assets measured at net asset value	5.4	20.1
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance, beginning of year	20.1
Balance, end of year	5.4	20.1
Other | Significant Unobservable Inputs (Level 3)
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	0.2
Unrealized gains	0.7	1.1
Purchases
Sales	(0.9)	(1.3)
Balance, end of year	11.4	11.4
Short-term Investments
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan fair value of plan assets measured at net asset value	83.9	81.8
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance, beginning of year	81.8
Balance, end of year	83.9	81.8
Short-term Investments | Investments Measured at NAV [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan fair value of plan assets measured at net asset value	83.9	81.8
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance, beginning of year	81.8
Balance, end of year	$ 83.9	$ 81.8