Senior Notes and Long-Term Debt - Senior Notes (Detail) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2021	Dec. 31, 2020
Debt Instrument [Line Items]
Senior Notes	$ 2,505.5	$ 3,122.4
Fixed Rate Due Aug. 2021
Debt Instrument [Line Items]
Interest rate	3.375%
Senior Notes	$ 0.0	499.8
Fixed Rate Due Aug. 2022
Debt Instrument [Line Items]
Interest rate	2.375%
Senior Notes	$ 499.8	499.6
Fixed Rate Due Aug. 2028
Debt Instrument [Line Items]
Interest rate	3.65%
Senior Notes	$ 548.5	584.4
Fixed Rate Due May. 2029
Debt Instrument [Line Items]
Interest rate	3.15%
Senior Notes	$ 533.9	567.9
Fixed Rate Due May. 2030
Debt Instrument [Line Items]
Interest rate	1.95%
Senior Notes	$ 923.3	970.7
Senior Notes
Debt Instrument [Line Items]
Debt issue costs	2.9
Senior Notes \| Interest Rate Swaps
Debt Instrument [Line Items]
Change in unrealized gain (loss) on hedged item in fair value hedge	$ 12.5	$ 130.7

Amount of the increase (decrease) in fair value of the hedged item in a fair value hedge recognized in the income statement.

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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 issuance costs. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs.

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Including the current and noncurrent portions, carrying value as of the balance sheet date of Notes with the highest claim on the assets of the issuer in case of bankruptcy or liquidation (with maturities initially due after one year or beyond the operating cycle if longer). Senior note holders are paid off in full before any payments are made to junior note holders.

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