Borrowings (Details) € in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2020 USD ($)	Mar. 31, 2020 EUR (€)	Dec. 31, 2019 USD ($)
Short-term borrowings [Abstract]
Commercial Paper	$ 0		$ 84,700
Notes payable and current maturities of long-term debt	500,000		84,700
Long-term borrowings [Abstract]
Net long-term debt	2,963,018		2,985,716
Unamortized debt discounts	18,300		18,900
Deferred debt issuance costs	15,700		16,200
Line of Credit Facility [Abstract]
Unsecured revolving credit facility, maximum borrowing capacity	$ 1,000,000
Line of Credit Facility, Covenant Compliance	The Company was in compliance with all covenants in the Credit Agreement and other long-term debt covenants at March 31, 2020 and had an interest coverage ratio of consolidated EBITDA to consolidated net interest expense of 11.2 to 1.
Letters of Credit Outstanding, Amount	$ 143,500
Current poriton of long-term debt and short-term borrowings	500,000		0
Note due 2025 [Member]
Long-term borrowings [Abstract]
Long-term debt	396,210		396,042
Debt Instrument, Face Amount	400,000
Note due 2026 [Member]
Long-term borrowings [Abstract]
Long-term debt	645,487		658,089
Debt Instrument, Face Amount | €		€ 600,000
Debentures due 2028 [Member]
Long-term borrowings [Abstract]
Long-term debt	199,180		199,155
Debt Instrument, Face Amount	200,000
Debenture due 2035 [Member]
Long-term borrowings [Abstract]
Long-term debt	296,122		296,060
Debt Instrument, Face Amount	300,000
Note due 2038 [Member]
Long-term borrowings [Abstract]
Long-term debt	247,968		247,939
Debt Instrument, Face Amount	250,000
Note due 2041 [Member]
Long-term borrowings [Abstract]
Long-term debt	344,222		344,153
Debt Instrument, Face Amount	350,000
Note due 2027 [Member]
Long-term borrowings [Abstract]
Long-term debt	537,463		548,008
Debt Instrument, Face Amount | €		€ 500,000
Notes due 2029
Long-term borrowings [Abstract]
Long-term debt	296,366		$ 296,270
Debt Instrument, Face Amount	$ 300,000