Debt and Credit Arrangements Debt Transactions (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Debt Instrument [Line Items]
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, before Tax	$ 1.0	$ 1.1	$ 2.8	$ 1.7
Unsecured Debt 4.65% Notes [Member]
Debt Instrument [Line Items]
Par Value	$ 500.0		$ 500.0
Debt Instrument, Interest Rate, Stated Percentage	4.65%		4.65%
Maturity Date			Oct. 01, 2028
Debt Instrument, Unamortized Discount (Premium), Net	$ 0.7		$ 0.7
Debt Issuance Costs, Net	1.8		1.8
4.750% Notes Due 2030 (less unamortized discount and issuance costs of $2.8 and $4.1, respectively)
Debt Instrument [Line Items]
Par Value	$ 650.0		$ 650.0
Debt Instrument, Interest Rate, Stated Percentage	4.75%		4.75%
Maturity Date			Mar. 30, 2030
Debt Instrument, Unamortized Discount (Premium), Net	$ 2.3		$ 2.3
Debt Issuance Costs, Net	$ 3.4		$ 3.4
Unsecured Debt 2.400% Note [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	2.40%		2.40%
2.400% Notes Due 2031 (less unamortized discount and issuance costs of $0.6 and $3.6, respectively)
Debt Instrument [Line Items]
Par Value	$ 500.0		$ 500.0
Maturity Date			Mar. 01, 2031
Debt Instrument, Unamortized Discount (Premium), Net	0.5		$ 0.5
Debt Issuance Costs, Net	3.0		$ 3.0
3.375% Notes Due 2041 (less unamortized discount and issuance costs of $1.0 and $5.1, respectively)
Debt Instrument [Line Items]
Maturity Date			Mar. 01, 2041
Debt Instrument, Unamortized Discount (Premium), Net	1.0		$ 1.0
Debt Issuance Costs, Net	4.7		4.7
Unsecured Debt 5.40% Notes [Member]
Debt Instrument [Line Items]
Par Value	$ 500.0		$ 500.0
Debt Instrument, Interest Rate, Stated Percentage	5.40%		5.40%
Maturity Date			Oct. 01, 2048
Debt Instrument, Unamortized Discount (Premium), Net	$ 2.5		$ 2.5
Debt Issuance Costs, Net	4.5		4.5
Unsecured Debt 3.375% Note
Debt Instrument [Line Items]
Par Value	$ 500.0		$ 500.0
Debt Instrument, Interest Rate, Stated Percentage	3.375%		3.375%
Unsecured Debt 4.200% Notes Remaining Principal
Debt Instrument [Line Items]
Par Value	$ 250.0		$ 250.0
Debt Instrument, Interest Rate, Stated Percentage	4.20%		4.20%
5.375% Notes Due 2033 (less unamortized discount and issuance costs of $3.7 and $3.3, respectively)
Debt Instrument [Line Items]
Par Value	$ 300.0		$ 300.0
Debt Instrument, Interest Rate, Stated Percentage	5.375%		5.375%
Maturity Date			Jun. 15, 2033
Debt Instrument, Unamortized Discount (Premium), Net	$ 3.4		$ 3.4
Debt Issuance Costs, Net	$ 2.8		$ 2.8