Long-Term Debt - Long-Term Debt (Detail) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Debt Instrument [Line Items]
Total debt	$ 3,117,061	$ 3,120,481
Less: Current maturities of long-term debt and short-term facilities	(385,043)	(390,042)
Long-term debt	2,732,018	2,730,439
4.25% Senior Notes, Due 2024
Debt Instrument [Line Items]
Total debt	396,697	396,398
7% Debentures, Due 2025
Debt Instrument [Line Items]
Total debt	124,319	124,272
3.450% Senior Notes, Due 2027
Debt Instrument [Line Items]
Total debt	297,098	296,939
3.500% Senior Notes, Due 2027
Debt Instrument [Line Items]
Total debt	495,011	494,765
6.25% Senior Notes, Due 2037
Debt Instrument [Line Items]
Total debt	228,126	228,094
4.250% Senior Notes, Due 2047
Debt Instrument [Line Items]
Total debt	591,626	591,541
Floating Rate Senior Notes, Due 2019
Debt Instrument [Line Items]
Total debt	299,633	299,260
Floating Rate Senior Notes, Due 2020
Debt Instrument [Line Items]
Total debt	299,323	298,956
Other Notes
Debt Instrument [Line Items]
Total debt	228	256
Trade Receivable Facility
Debt Instrument [Line Items]
Total debt	$ 385,000	$ 390,000

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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, 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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