Long-Term Debt And Commercial Paper (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2024	Dec. 31, 2023
Debt Instrument [Line Items]
Letters of credit, amount outstanding	$ 0.8
Commercial paper, maximum aggregate amount outstanding permitted	1,900.0
Commercial paper, amount outstanding	$ 285.0	$ 440.0
Commercial Paper
Debt Instrument [Line Items]
Weighted-average annual interest rate	5.90%	5.90%
Maximum | Commercial Paper
Debt Instrument [Line Items]
Maturity period of debt	397 days
Weighted Average | Commercial Paper
Debt Instrument [Line Items]
Maturity period of debt	4 days	6 days
Revolving Credit Facility Due 2028
Debt Instrument [Line Items]
Maximum borrowing capacity under revolving credit facility	$ 1,900.0
Additional borrowing capacity under accordion feature of revolving credit facility	500.0
Revolving credit facilities letter of credit sublimit	200.0
Additional borrowing capacity under the revolving credit facility	1,900.0
Revolving Credit Facility Due 2028 | Recourse
Debt Instrument [Line Items]
Revolving credit facility, amount outstanding	$ 0.0	$ 0.0
Revolving Credit Facility Due 2028 | Secured Overnight Financing Rate (SOFR)
Debt Instrument [Line Items]
Credit spread adjustment on SOFR borrowings under our revolving credit facility	0.10%
Revolving Credit Facility Due 2028 | Minimum
Debt Instrument [Line Items]
Commitment fee on undrawn amounts (percent)	0.125%
Revolving Credit Facility Due 2028 | Maximum
Debt Instrument [Line Items]
Commitment fee on undrawn amounts (percent)	0.20%
Other Debt | Recourse
Debt Instrument [Line Items]
Finance leases and other debt obligations included in long-term debt	$ 359.7	$ 362.2
Line of Credit | Revolving Credit Facility Due 2028 | Recourse
Debt Instrument [Line Items]
Maturity date	Jul. 18, 2028
Line of Credit | Revolving Credit Facility Due 2028 | Minimum | Secured Overnight Financing Rate (SOFR)
Debt Instrument [Line Items]
Basis spread on variable interest rates (percent)	1.125%
Line of Credit | Revolving Credit Facility Due 2028 | Minimum | Base Rate
Debt Instrument [Line Items]
Basis spread on variable interest rates (percent)	0.125%
Line of Credit | Revolving Credit Facility Due 2028 | Maximum | Secured Overnight Financing Rate (SOFR)
Debt Instrument [Line Items]
Basis spread on variable interest rates (percent)	1.50%
Line of Credit | Revolving Credit Facility Due 2028 | Maximum | Base Rate
Debt Instrument [Line Items]
Basis spread on variable interest rates (percent)	0.50%