Carrying value as of the balance sheet date of short-term borrowings using unsecured obligations issued by banks, corporations and other borrowers to investors. The maturities of these money market securities generally do not exceed 270 days.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(13)(2))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(16))
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(19)(a)(3))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Borrowings (Details) € in Thousands, $ in Thousands	3 Months Ended
Borrowings (Details) € in Thousands, $ in Thousands	Mar. 31, 2019 USD ($)	Mar. 31, 2019 EUR (€)	Dec. 31, 2018 USD ($)
Short-term borrowings [Abstract]
Current poriton of long-term debt and short-term borrowings	$ 1,355		$ 0
Commercial Paper	344,900		220,318
Notes payable and current maturities of long-term debt	346,255		220,318
Long-term borrowings [Abstract]
Long-term debt	2,940,967		2,943,660
Long-term debt current portion	0		0
Net long-term debt	2,940,967		2,943,660
Unamortized debt discounts	15,400		15,800
Deferred debt issuance costs	12,600		13,000
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, 2019 and had a coverage ratio of 9.7 to 1.0.
Letters of Credit Outstanding, Amount	$ 142,400
Note due 2020 [Member]
Long-term borrowings [Abstract]
Long-term debt	338,583		339,657
Debt Instrument, Face Amount \| €		€ 300,000
Note due 2021 [Member]
Long-term borrowings [Abstract]
Long-term debt	449,293		449,200
Debt Instrument, Face Amount	450,000
Note due 2025 [Member]
Long-term borrowings [Abstract]
Long-term debt	395,537		395,368
Debt Instrument, Face Amount	400,000
Note due 2026 [Member]
Long-term borrowings [Abstract]
Long-term debt	670,021		672,103
Debt Instrument, Face Amount \| €		€ 600,000
Debentures due 2028 [Member]
Long-term borrowings [Abstract]
Long-term debt	199,080		199,054
Debt Instrument, Face Amount	200,000
Debenture due 2035 [Member]
Long-term borrowings [Abstract]
Long-term debt	295,873		295,811
Debt Instrument, Face Amount	300,000
Note due 2038 [Member]
Long-term borrowings [Abstract]
Long-term debt	247,855		247,827
Debt Instrument, Face Amount	250,000
Note due 2041 [Member]
Long-term borrowings [Abstract]
Long-term debt	343,946		343,877
Debt Instrument, Face Amount	350,000
Other long term debt instruments [Member]
Long-term borrowings [Abstract]
Long-term debt	$ 779		$ 763