Debt and Credit Agreements Long-Term Debt (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2022	Dec. 31, 2021
Debt Instrument [Line Items]
Long-term debt, gross	$ 2,871.3	$ 2,909.3
Long-term debt, current maturities	0.6	0.7
Long-term debt, excluding current maturities	2,870.7	2,908.6
Deb instrument, unamortized debt issuance costs	26.2	29.4
Long-term debt, fair value	2,552.3	3,337.4
4.000% Notes Due 2022
Debt Instrument [Line Items]
Senior Notes	$ 250.0
Interest rate, stated percentage	4.00%
3.750% Notes Due 2023
Debt Instrument [Line Items]
Senior Notes	$ 500.0
Interest rate, stated percentage	3.75%
4.200% Notes Due 2024 (less unamortized discount and issuance costs of $0.1 and $0.5, respectively)
Debt Instrument [Line Items]
Senior Notes	$ 250.0
Long-term debt, gross	249.7	249.4
Debt instrument, unamortized discount	0.0
Deb instrument, unamortized debt issuance costs	$ 0.3
Debt instrument, maturity date	Apr. 15, 2024
Interest rate, stated percentage	4.20%
Debt instrument, interest rate, effective percentage	4.24%
4.650% Notes Due 2028 (less unamortized discount and issuance costs of $1.2 and $3.0, respectively)
Debt Instrument [Line Items]
Senior Notes	$ 500.0
Long-term debt, gross	496.4	495.8
Debt instrument, unamortized discount	1.0
Deb instrument, unamortized debt issuance costs	$ 2.6
Debt instrument, maturity date	Oct. 01, 2028
Interest rate, stated percentage	4.65%
Debt instrument, interest rate, effective percentage	4.78%
4.750% Note Due 2030 (less unamortized discount and issuance costs of $3.2 and $5.1, respectively)
Debt Instrument [Line Items]
Senior Notes	$ 650.0
Long-term debt, gross	642.6	641.7
Debt instrument, unamortized discount	2.9
Deb instrument, unamortized debt issuance costs	$ 4.5
Debt instrument, maturity date	Mar. 30, 2030
Interest rate, stated percentage	4.75%
Debt instrument, interest rate, effective percentage	4.92%
2.400% Note Due 2031 (less unamortized discount and issuance costs of $0.7 and $4.3, respectively)
Debt Instrument [Line Items]
Senior Notes	$ 500.0
Long-term debt, gross	495.5	495.0
Debt instrument, unamortized discount	0.7
Deb instrument, unamortized debt issuance costs	$ 3.8
Debt instrument, maturity date	Mar. 01, 2031
Interest rate, stated percentage	2.40%
Debt instrument, interest rate, effective percentage	2.512%
3.375% Note Due 2041 (less unamortized discount and issuance costs of $1.1 and $5.5, respectively)
Debt Instrument [Line Items]
Senior Notes	$ 500.0
Long-term debt, gross	493.7	493.4
Debt instrument, unamortized discount	1.0
Deb instrument, unamortized debt issuance costs	$ 5.3
Debt instrument, maturity date	Mar. 01, 2041
Interest rate, stated percentage	3.375%
Debt instrument, interest rate, effective percentage	3.448%
5.40% Notes Due 2048 (less unamortized discount and issuance costs of $2.7 and $5.0, respectively)
Debt Instrument [Line Items]
Senior Notes	$ 500.0
Long-term debt, gross	492.6	492.3
Debt instrument, unamortized discount	2.6
Deb instrument, unamortized debt issuance costs	$ 4.8
Debt instrument, maturity date	Oct. 01, 2048
Interest rate, stated percentage	5.40%
Debt instrument, interest rate, effective percentage	5.48%
Other notes payable and capitalized leases
Debt Instrument [Line Items]
Long-term debt, gross	$ 0.8	$ 41.7

Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

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Face (par) amount of debt instrument at time of issuance.

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Effective interest rate for the funds borrowed under the debt agreement considering interest compounding and original issue discount or premium.

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Contractual interest rate for funds borrowed, under the debt agreement.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Date when the debt instrument is scheduled to be fully repaid, in YYYY-MM-DD format.

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Amount, after accumulated amortization, of debt discount.

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Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt, classified as current. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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The fair value amount of long-term debt whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission.

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Amount, excluding unamortized premium (discount) and debt issuance cost, of long-term debt classified as noncurrent. Excludes lease obligation.

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The remaining balance of debt issuance expenses that were capitalized and are being amortized against income over the lives of the respective bond issues. This does not include the amounts capitalized as part of the cost of the utility plant or asset.

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