Borrowings (Details) € in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Dec. 31, 2016 EUR (€)	Sep. 30, 2016 USD ($)
Letters of Credit [Abstract]
Letters of credit outstanding	$ 140,900
Maturities of Long-term Debt [Abstract]
2017	6,950
2018	350,357
2019	0
2020	313,370
2021	449,891
2022 and thereafter	2,109,505
Total long term debt (including current portion)	3,230,073
Interest expense and interest income [Abstract]
Interest expense	136,401	$ 131,676	$ 131,689
Interest income	(6,759)	(4,419)	(4,510)
Interest expense, net	129,642	127,257	$ 127,179
Short-term borrowings [Abstract]
Long-term Debt, Current Maturities	6,950	122
Commercial paper	407,600	151,000
Total short-term debt	414,550	151,122
Long-term borrowings [Abstract]
Long-term Debt	3,223,123	2,617,342
Deferred Finance Costs, Own-share Lending Arrangement, Issuance Costs, Net	16,486	13,687
Total long-term debt	3,206,637	2,603,655
Unamortized discount	18,832	13,951
Proceeds from Issuance of Debt	$ 656,399
Line of Credit Facility [Abstract]
Line of credit facility, interest rate description	At the Company's election, loans under the Credit Agreement will bear interest at a base rate plus an applicable margin.
Line of credit facility, covenant terms	the Credit Agreement requires the Company to pay a facility fee and imposes various restrictions on the Company such as, among other things, the requirement for the Company to maintain an interest coverage ratio of consolidated EBITDA to consolidated net interest expense of not less than 3.0 to 1
Line of credit facility, covenant compliance	The Company was in compliance with this covenant and other long-term debt covenants at December 31, 2016 and had a coverage ratio of 9.4 to 1.
term loan agreement					$ 500,000
Note due 2018 [Member]
Long-term borrowings [Abstract]
Long-term Debt	$ 349,588	349,258
Debt instrument, stated interest rate (in hundredths)	5.45%			5.45%
Term of debt instrument (in years)	10 years
Debt instruments, maturity date	Mar. 15, 2018
Note due 2020 [Member]
Long-term borrowings [Abstract]
Long-term Debt	$ 313,370	328,592
Debt instrument, stated interest rate (in hundredths)	2.125%			2.125%
Term of debt instrument (in years)	7 years
Debt instruments, maturity date	Dec. 01, 2020
Note due 2021 [Member]
Long-term borrowings [Abstract]
Long-term Debt	$ 449,891	449,865
Debt instrument, stated interest rate (in hundredths)	4.30%			4.30%
Term of debt instrument (in years)	10 years
Debt instruments, maturity date	Mar. 01, 2021
Note due 2025 [Member]
Long-term borrowings [Abstract]
Long-term Debt	$ 397,259	396,951
Debt instrument, stated interest rate (in hundredths)	3.15%			3.15%
Term of debt instrument (in years)	10 years
Debt instruments, maturity date	Nov. 15, 2025
Note due 2026 [Member]
Long-term borrowings [Abstract]
Long-term Debt	$ 621,326	0
Debt instrument, stated interest rate (in hundredths)	1.25%			1.25%
Term of debt instrument (in years)	10 years
Debt instruments, maturity date	Nov. 09, 2026
Face amount of notes | €				€ 600,000
Debentures due 2028 [Member]
Long-term borrowings [Abstract]
Long-term Debt	$ 199,586	199,552
Debt instrument, stated interest rate (in hundredths)	6.65%			6.65%
Term of debt instrument (in years)	30 years
Debt instruments, maturity date	Jun. 01, 2028
Debenture due 2035 [Member]
Long-term borrowings [Abstract]
Long-term Debt	$ 297,003	296,844
Debt instrument, stated interest rate (in hundredths)	5.375%			5.375%
Term of debt instrument (in years)	30 years
Debt instruments, maturity date	Oct. 15, 2035
Note due 2038 [Member]
Long-term borrowings [Abstract]
Long-term Debt	$ 248,124	248,036
Debt instrument, stated interest rate (in hundredths)	6.60%			6.60%
Term of debt instrument (in years)	30 years
Debt instruments, maturity date	Mar. 15, 2038
Note due 2041 [Member]
Long-term borrowings [Abstract]
Long-term Debt	$ 346,147	345,989
Debt instrument, stated interest rate (in hundredths)	5.375%			5.375%
Term of debt instrument (in years)	30 years
Debt instruments, maturity date	Mar. 01, 2041
Other long term debt instruments [Member]
Long-term borrowings [Abstract]
Long-term Debt	$ 829	$ 2,255
Commercial Paper [Member]
Line of Credit Facility [Abstract]
Short-term Debt, Weighted Average Interest Rate	0.60%	0.20%	0.10%	0.60%
Credit Agreement [Member]
Line of Credit Facility [Abstract]
Line of Credit Facility, Maximum Borrowing Capacity	$ 1,000,000
Credit facility expiration date	Nov. 10, 2020
Minimum [Member]
Line of Credit Facility [Abstract]
Credit facility expiration date	Dec. 31, 2017
Maximum [Member]
Line of Credit Facility [Abstract]
Credit facility expiration date	Dec. 31, 2021