Debt - Summary of Long-Term Debt and Related Weighted Average Interest Rates (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2017
Debt Instrument [Line Items]
Long-Term Debt	$ 2,320.3	$ 2,334.4
Other	1.4
Debt and lease obligation, gross	2,321.7
Unamortized Debt Issuance Costs	(16.2)	(16.1)
Unamortized Original Issue Premium (Discount)	9.0	(10.5)
Long-Term Debt, Net		2,307.8
Less — Current portion		(14.1)
Long-term debt		2,293.7
Debt and lease obligation	2,314.5
Less — Current portion	(14.2)	(14.1)
Long-term debt	2,300.3	2,293.7
Senior Notes \| 5.25% Senior Notes due 2025 (the "2025 Notes")
Debt Instrument [Line Items]
Long-Term Debt	650.0	650.0
Unamortized Debt Issuance Costs		(4.2)
Unamortized Original Issue Premium (Discount)		0.0
Long-Term Debt, Net		$ 645.8
Weighted Average Interest Rate		5.25%
Stated interest rate		5.25%
Senior Notes \| 3.8% Senior Notes due 2027 (the "2027 Notes")
Debt Instrument [Line Items]
Long-Term Debt	750.0	$ 750.0
Unamortized Debt Issuance Costs	(4.1)	(4.7)
Unamortized Original Issue Premium (Discount)	(3.5)	(4.1)
Long-Term Debt, Net	$ 742.4	$ 741.2
Weighted Average Interest Rate	3.885%	3.885%	3.885%
Stated interest rate	3.80%		3.80%
Senior Notes \| 4.25% Senior Notes due 2029 (the "2029 Notes")
Debt Instrument [Line Items]
Long-Term Debt	$ 375.0	$ 375.0
Unamortized Debt Issuance Costs	(2.6)	(2.9)
Unamortized Original Issue Premium (Discount)	(1.0)	(1.1)
Long-Term Debt, Net	$ 371.4	$ 371.0
Weighted Average Interest Rate	4.288%	4.288%
Stated interest rate	4.25%	4.25%
Senior Notes \| 3.5% Senior Notes due 2030 (the "2030 Notes")
Debt Instrument [Line Items]
Long-Term Debt	$ 350.0
Unamortized Debt Issuance Costs	(2.6)
Unamortized Original Issue Premium (Discount)	(0.7)
Long-Term Debt, Net	$ 346.7
Weighted Average Interest Rate	3.525%
Stated interest rate	3.50%
Senior Notes \| 5.25% Senior Notes due 2049 (the "2049 Notes")
Debt Instrument [Line Items]
Long-Term Debt	$ 625.0
Unamortized Debt Issuance Costs	(6.3)
Unamortized Original Issue Premium (Discount)	14.2
Long-Term Debt, Net	$ 632.9
Weighted Average Interest Rate	5.103%
Stated interest rate	5.25%
Senior Notes \| 2049 Notes
Debt Instrument [Line Items]
Long-Term Debt		$ 325.0
Unamortized Debt Issuance Costs		(3.3)
Unamortized Original Issue Premium (Discount)		(5.3)
Long-Term Debt, Net		$ 316.4
Weighted Average Interest Rate	4.821%	5.363%
Stated interest rate	5.25%	5.25%
Term Loan Facility \| Credit Agreement \| Credit Agreement — Term Loan Facility
Debt Instrument [Line Items]
Long-Term Debt	$ 220.3	$ 234.4
Unamortized Debt Issuance Costs	(0.6)	(1.0)
Unamortized Original Issue Premium (Discount)	0.0	0.0
Long-Term Debt, Net	$ 219.7	$ 233.4
Weighted Average Interest Rate	1.36%	2.88%

Debt and Lease Obligation, Gross

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Amount of short-term and long-term debt and lease obligation.

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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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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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Amount, after accumulated amortization, of debt discount (premium).

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Amount, after accumulated amortization, of debt issuance costs. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs.

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Present value of lessee's discounted obligation for lease payments from finance lease.

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

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Amount of long-term debt and lease obligation, classified as noncurrent.

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Amount of long-term debt and lease obligation, classified as current.

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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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Amount after unamortized (discount) premium and debt issuance costs of long-term debt classified as noncurrent and excluding amounts to be repaid within one year or the normal operating cycle, if longer. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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