DEBT (Outstanding Debt) (Details) $ / shares in Units, $ in Thousands, € in Millions			1 Months Ended	3 Months Ended		12 Months Ended
	Mar. 31, 2016 USD ($)	Aug. 20, 2014 USD ($) Days $ / shares	May 31, 2013 USD ($) Days $ / shares	Mar. 31, 2018 USD ($)	Mar. 31, 2017 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)	Mar. 31, 2018 EUR (€)	Dec. 31, 2017 EUR (€)	Aug. 15, 2017 USD ($)	Mar. 10, 2017 EUR (€)	May 23, 2016 USD ($)	Nov. 25, 2015 EUR (€)	Mar. 13, 2015 USD ($)	Mar. 03, 2015 EUR (€)	Sep. 23, 2014 EUR (€)	Jun. 30, 2013 USD ($)	Mar. 31, 2012 USD ($) $ / shares
Debt Instrument
Outstanding Principal Amount, Long-term debt				$ 8,111,938		$ 9,003,000
Unamortized Debt Discount and Debt Issuance Cost				(121,520)		(193,212)
Carrying Value, Long-term debt				7,990,418		8,809,788
Description of Senior Notes
Convertible debt				51,398		2,963
Payments Related to Conversion of Senior Notes				1,487,109	$ 4
Amortization of debt discount included in interest expense				15,127	17,625
0.35% Convertible Senior Notes due June 2020
Debt Instrument
Outstanding Principal Amount, Short-term debt				1,000,000
Outstanding Principal Amount, Long-term debt						1,000,000
Unamortized Debt Discount and Debt Issuance Cost				(58,343)		(64,825)
Carrying value, Short-term debt				941,657
Carrying Value, Long-term debt						$ 935,175
Description of Senior Notes
Convertible debt				$ 51,400
Aggregate principal amount			$ 1,000,000
Interest rate on Long-term Debt			0.35%	0.35%		0.35%					0.35%	0.35%
Debt financing costs paid										$ 1,000
Convertible debt conversion price (in dollars per share) | $ / shares			$ 1,315.10
Ratio of closing share price to conversion price as a condition for conversion of the convertible notes, minimum			150.00%
Unamortized debt discount			$ 20,000
Effective interest rate at debt origination or modification			3.13%
Debt discount related to convertible notes, net of tax																				$ 92,400
Debt discount related to convertible notes, before tax																				154,300
Convertible carrying amount of equity component related to finance costs net of tax																				$ 100
Amortization of debt discount included in interest expense				$ 700	700
0.9% Convertible Senior Notes due September 2021
Debt Instrument
Outstanding Principal Amount, Long-term debt				1,000,000		$ 1,000,000
Unamortized Debt Discount and Debt Issuance Cost				(77,838)		(83,272)
Carrying Value, Long-term debt				$ 922,162		$ 916,728
Description of Senior Notes
Aggregate principal amount		$ 1,000,000
Interest rate on Long-term Debt		0.90%		0.90%		0.90%					0.90%	0.90%
Debt financing costs paid									$ 11,000
Convertible debt conversion price (in dollars per share) | $ / shares		$ 2,055.50
Ratio of closing share price to conversion price as a condition for conversion of the convertible notes, minimum		150.00%
Effective interest rate at debt origination or modification		3.18%
Debt discount related to convertible notes, net of tax									82,500
Debt discount related to convertible notes, before tax									142,900
Convertible carrying amount of equity component related to finance costs net of tax									1,600
0.8% (€1 Billion) Senior Notes due March 2022
Debt Instrument
Outstanding Principal Amount, Long-term debt				$ 1,229,850		$ 1,200,800
Unamortized Debt Discount and Debt Issuance Cost				(5,916)		(6,238)
Carrying Value, Long-term debt				$ 1,223,934		$ 1,194,562
Description of Senior Notes
Aggregate principal amount | €											€ 1,000.0	€ 1,000.0		€ 1,000.0
Interest rate on Long-term Debt				0.80%		0.80%					0.80%	0.80%		0.80%
Debt financing costs paid						$ 5,000
Unamortized debt discount | €														€ 2.1
Effective interest rate at debt origination or modification														0.84%
2.15% (€750 Million) Senior Notes due November 2022
Debt Instrument
Outstanding Principal Amount, Long-term debt				$ 922,388		900,600
Unamortized Debt Discount and Debt Issuance Cost				(4,493)		(4,683)
Carrying Value, Long-term debt				$ 917,895		$ 895,917
Description of Senior Notes
Aggregate principal amount | €											€ 750.0	€ 750.0				€ 750.0
Interest rate on Long-term Debt				2.15%		2.15%					2.15%	2.15%				2.15%
Debt financing costs paid								$ 3,700
Unamortized debt discount | €																€ 2.2
Effective interest rate at debt origination or modification																2.20%
2.75% Senior Notes due March 2023
Debt Instrument
Outstanding Principal Amount, Long-term debt				$ 500,000		$ 500,000
Unamortized Debt Discount and Debt Issuance Cost				(3,051)		(3,203)
Carrying Value, Long-term debt				$ 496,949		$ 496,797
Description of Senior Notes
Aggregate principal amount													$ 500,000
Interest rate on Long-term Debt				2.75%		2.75%					2.75%	2.75%	2.75%
Debt financing costs paid						$ 2,700
Unamortized debt discount													$ 700
Effective interest rate at debt origination or modification													2.78%
2.375% (€1 Billion) Senior Notes due September 2024
Debt Instrument
Outstanding Principal Amount, Long-term debt				$ 1,229,850		1,200,800
Unamortized Debt Discount and Debt Issuance Cost				(11,992)		(12,240)
Carrying Value, Long-term debt				$ 1,217,858		$ 1,188,560
Description of Senior Notes
Aggregate principal amount | €											€ 1,000.0	€ 1,000.0							€ 1,000.0
Interest rate on Long-term Debt				2.375%		2.375%					2.375%	2.375%							2.375%
Debt financing costs paid									$ 6,500
Unamortized debt discount | €																			€ 9.4
Effective interest rate at debt origination or modification																			2.48%
3.65% Senior Notes due March 2025
Debt Instrument
Outstanding Principal Amount, Long-term debt				$ 500,000		$ 500,000
Unamortized Debt Discount and Debt Issuance Cost				(3,180)		(3,290)
Carrying Value, Long-term debt				$ 496,820		$ 496,710
Description of Senior Notes
Aggregate principal amount																	$ 500,000
Interest rate on Long-term Debt				3.65%		3.65%					3.65%	3.65%					3.65%
Debt financing costs paid								3,200
Unamortized debt discount																	$ 1,300
Effective interest rate at debt origination or modification																	3.68%
3.6% Senior Notes due June 2026
Debt Instrument
Outstanding Principal Amount, Long-term debt				$ 1,000,000		$ 1,000,000
Unamortized Debt Discount and Debt Issuance Cost				(6,644)		(6,840)
Carrying Value, Long-term debt				$ 993,356		$ 993,160
Description of Senior Notes
Aggregate principal amount															$ 1,000,000
Interest rate on Long-term Debt				3.60%		3.60%					3.60%	3.60%			3.60%
Debt financing costs paid							$ 6,200
Unamortized debt discount															$ 1,900
Effective interest rate at debt origination or modification															3.62%
1.8% (€1 Billion) Senior Notes due March 2027
Debt Instrument
Outstanding Principal Amount, Long-term debt				$ 1,229,850		$ 1,200,800
Unamortized Debt Discount and Debt Issuance Cost				(5,004)		(5,136)
Carrying Value, Long-term debt				$ 1,224,846		$ 1,195,664
Description of Senior Notes
Aggregate principal amount | €											€ 1,000.0	€ 1,000.0						€ 1,000.0
Interest rate on Long-term Debt				1.80%		1.80%					1.80%	1.80%						1.80%
Debt financing costs paid								$ 6,300
Unamortized debt discount | €																		€ 0.3
Effective interest rate at debt origination or modification																		1.80%
3.55% Senior Notes due March 2028
Debt Instrument
Outstanding Principal Amount, Long-term debt				$ 500,000		$ 500,000
Unamortized Debt Discount and Debt Issuance Cost				(3,402)		(3,485)
Carrying Value, Long-term debt				$ 496,598		$ 496,515
Description of Senior Notes
Aggregate principal amount													$ 500,000
Interest rate on Long-term Debt				3.55%		3.55%					3.55%	3.55%	3.55%
Debt financing costs paid						$ 3,200
Unamortized debt discount													$ 400
Effective interest rate at debt origination or modification													3.56%
Convertible Debt 1.00 Percent Due March 2018 [Member]
Debt Instrument
Outstanding Principal Amount, Short-term debt						714,304
Unamortized Debt Discount and Debt Issuance Cost						(3,394)
Carrying value, Short-term debt						710,910
Description of Senior Notes
Convertible debt						$ 3,000
Aggregate principal amount																					$ 1,000,000
Interest rate on Long-term Debt						1.00%						1.00%									1.00%
Convertible debt conversion price (in dollars per share) | $ / shares																					$ 944.61
Payments Related to Conversion of Senior Notes				$ 714,300
Debt Conversion, Converted Instrument, Cash				773,200
Effective interest rate at debt origination or modification																					3.50%
Debt discount related to convertible notes, net of tax																					$ 80,900
Debt discount related to convertible notes, before tax																					135,200
Convertible carrying amount of equity component related to finance costs net of tax																					$ 2,800
Convertible Debt
Description of Senior Notes
Interest expense related to debt				19,800	24,000
Coupon Interest expense				4,500	5,600
Amortization of debt discount included in interest expense				14,500	17,200
Amortization of debt issuance costs				$ 800	$ 1,200
Debt, weighted average interest rate				3.30%	3.40%
Other Long-term Debt
Description of Senior Notes
Interest expense related to debt				$ 43,300	$ 30,600
Coupon Interest expense				41,600	29,500
1% CT Loan Due March 2016
Description of Senior Notes
Aggregate principal amount	$ 2,500			$ 1,500		$ 1,500
Interest rate on Long-term Debt	1.00%			1.00%		1.00%					1.00%	1.00%
Debt instrument, term	10 years
Debt instrument, decrease, forgiveness					$ 1,000
Minimum | 0.35% Convertible Senior Notes due June 2020
Description of Senior Notes
Minimum and Maximum consecutive days the closing sales price of common stock must exceed a specified percentage of conversion price to trigger conversion feature of note (in days) | Days			20
Additional payment to debt holder, settled In shares, aggregate value			$ 0
Minimum | 0.9% Convertible Senior Notes due September 2021
Description of Senior Notes
Minimum and Maximum consecutive days the closing sales price of common stock must exceed a specified percentage of conversion price to trigger conversion feature of note (in days) | Days		20
Additional payment to debt holder, settled In shares, aggregate value		$ 0
Maximum | 0.35% Convertible Senior Notes due June 2020
Description of Senior Notes
Minimum and Maximum consecutive days the closing sales price of common stock must exceed a specified percentage of conversion price to trigger conversion feature of note (in days) | Days			30
Additional payment to debt holder, settled In shares, aggregate value			$ 397,000
Maximum | 0.9% Convertible Senior Notes due September 2021
Description of Senior Notes
Minimum and Maximum consecutive days the closing sales price of common stock must exceed a specified percentage of conversion price to trigger conversion feature of note (in days) | Days		30
Additional payment to debt holder, settled In shares, aggregate value		$ 375,000
Level 2
Description of Senior Notes
Estimated market value of outstanding debt				$ 10,100,000		$ 11,100,000