Long-Term Debt - Long-Term Debt (Detail) - USD ($) $ in Millions	Jun. 30, 2023	Dec. 31, 2022
Debt Instrument [Line Items]
Total debt	$ 5,043.1	$ 5,040.0
Less: Current maturities	(700.0)	(699.1)
Long-term debt	4,343.1	4,340.9
0.650% Senior Notes, Due 2023 (discharged)
Debt Instrument [Line Items]
Total debt	700.0	699.1
4.250% Senior Notes, Due 2024
Debt Instrument [Line Items]
Total debt	399.3	398.9
7% Debentures, Due 2025
Debt Instrument [Line Items]
Total debt	124.7	124.7
3.450% Senior Notes, Due 2027
Debt Instrument [Line Items]
Total debt	298.5	298.3
3.500% Senior Notes, Due 2027
Debt Instrument [Line Items]
Total debt	491.9	491.5
2.500% Senior Notes, Due 2030
Debt Instrument [Line Items]
Total debt	471.0	470.5
2.400% Senior Notes, Due 2031
Debt Instrument [Line Items]
Total debt	889.0	888.6
6.25% Senior Notes, Due 2037
Debt Instrument [Line Items]
Total debt	228.4	228.4
4.250% Senior Notes, Due 2047
Debt Instrument [Line Items]
Total debt	590.3	590.2
3.200% Senior Notes, Due 2051
Debt Instrument [Line Items]
Total debt	$ 850.0	$ 849.8