Debt - Summary of Long-Term Debt and Related Weighted Average Interest Rates (Detail) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018	Aug. 31, 2017
Debt Instrument [Line Items]
Long-term debt and other	$ 2,334.4	$ 1,972.3
Unamortized Debt Issuance Costs	(16.1)	(13.8)
Unamortized Original Issue Discount	(10.5)	(4.6)
Long-Term Debt, Net	2,334.4	1,967.2
Long-term debt and other, net	2,307.8	1,953.9
Less — Current portion	(14.1)	(12.9)
Long-term debt	2,293.7	1,941.0
Other
Debt Instrument [Line Items]
Other		5.1
Credit Agreement — Term Loan Facility \| Term Loan Facility \| Credit Agreement
Debt Instrument [Line Items]
Long-Term Debt	234.4	242.2
Unamortized Debt Issuance Costs	(1.0)	(1.5)
Unamortized Original Issue Discount	0.0	0.0
Long-Term Debt, Net	$ 233.4	$ 240.7
Weighted Average Interest Rate	2.88%	3.92%
5.375% Senior Notes due 2024 (the 2024 Notes) \| Senior Notes
Debt Instrument [Line Items]
Long-Term Debt	$ 325.0	$ 325.0
Unamortized Debt Issuance Costs		(2.0)
Unamortized Original Issue Discount		0.0
Long-Term Debt, Net		$ 323.0
Weighted Average Interest Rate		5.375%
5.25% Senior Notes due 2025 (the 2025 Notes) \| Senior Notes
Debt Instrument [Line Items]
Long-Term Debt	650.0	$ 650.0
Unamortized Debt Issuance Costs	(4.2)	(5.0)
Unamortized Original Issue Discount	0.0	0.0
Long-Term Debt, Net	$ 645.8	$ 645.0
Weighted Average Interest Rate	5.25%	5.25%
Stated interest rate	5.25%
3.8% Senior Notes due 2027 (the 2027 Notes) \| Senior Notes
Debt Instrument [Line Items]
Long-Term Debt	$ 750.0	$ 750.0
Unamortized Debt Issuance Costs	(4.7)	(5.3)
Unamortized Original Issue Discount	(4.1)	(4.6)
Long-Term Debt, Net	$ 741.2	$ 740.1
Weighted Average Interest Rate	3.885%	3.885%	3.885%
Stated interest rate	3.80%		3.80%
4.25% Senior Notes due 2029 (the 2029 Notes) \| Senior Notes
Debt Instrument [Line Items]
Long-Term Debt	$ 375.0
Unamortized Debt Issuance Costs	(2.9)
Unamortized Original Issue Discount	(1.1)
Long-Term Debt, Net	$ 371.0
Weighted Average Interest Rate	4.288%
Stated interest rate	4.25%
5.25% Senior Notes due 2049 (the 2049 Notes) \| Senior Notes
Debt Instrument [Line Items]
Long-Term Debt	$ 325.0
Unamortized Debt Issuance Costs	(3.3)
Unamortized Original Issue Discount	(5.3)
Long-Term Debt, Net	$ 316.4
Weighted Average Interest Rate	5.363%
Stated interest rate	5.25%

Long-term Debt, Gross And Lease Obligation

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Amount equal to the present value (the principal) at the beginning of the lease term of minimum lease payments during the lease term (excluding that portion of the payments representing executory costs such as insurance, maintenance, and taxes to be paid by the lessor, together with any profit thereon) net of payments or other amounts applied to the principal through the balance sheet date.

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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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Amount, after accumulated amortization, of debt discount.

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

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