Debt and Credit Agreements Debt Transactions (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Schedule of New Debt Issuance [Line Items]
Recognition of previously unrealized gains included in net income	$ 3.8	$ 2.6	$ 1.4
4.20% Notes Due 2024
Schedule of New Debt Issuance [Line Items]
Debt Instrument, Face Amount	$ 250.0
Interest rate, stated percentage	4.20%
4.65% Notes Due 2028
Schedule of New Debt Issuance [Line Items]
Debt Instrument, Face Amount	$ 500.0
Interest rate, stated percentage	4.65%
4.75% Note Due 2030
Schedule of New Debt Issuance [Line Items]
Debt Instrument, Face Amount	$ 650.0
Interest rate, stated percentage	4.75%
5.40% Notes Due 2048
Schedule of New Debt Issuance [Line Items]
Debt Instrument, Face Amount	$ 500.0
Interest rate, stated percentage	5.40%
2.400% Note Due 2031 (less unamortized discount and issuance costs of $0.7 and $4.3, respectively)
Schedule of New Debt Issuance [Line Items]
Debt Instrument, Face Amount	$ 500.0
Interest rate, stated percentage	2.40%
3.375% Note Due 2041 (less unamortized discount and issuance costs of $1.1 and $5.5, respectively)
Schedule of New Debt Issuance [Line Items]
Debt Instrument, Face Amount	$ 500.0
Interest rate, stated percentage	3.375%
Unsecured Debt 5.375% Notes
Schedule of New Debt Issuance [Line Items]
Debt Instrument, Face Amount	$ 300.0
Interest rate, stated percentage	5.375%