DEBT (Narrative) (Details) - USD ($)			1 Months Ended		3 Months Ended			6 Months Ended		12 Months Ended
	Jun. 19, 2015	Aug. 20, 2014	May. 31, 2013	Mar. 31, 2012	Jun. 30, 2015	Mar. 31, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Jun. 30, 2013	Oct. 31, 2011	Mar. 31, 2010
Debt Instrument
Letters of credit issued					$ 3,800,000			$ 3,800,000		$ 4,000,000
Long-term Debt					5,399,966,000			5,399,966,000		3,849,756,000
Estimated market value of outstanding debt					6,000,000,000			6,000,000,000		4,800,000,000
Description of Senior Notes
Unamortized debt discount					328,198,000			328,198,000		360,312,000
Amortization of debt discount included in interest expense								33,211,000	$ 24,259,000
Gains (Losses) on Extinguishment of Debt								(3,000)	(6,129,000)
Convertible Notes [Member]
Description of Senior Notes
Interest expense related to debt					23,000,000		$ 16,400,000	46,300,000	33,400,000
Contractual coupon interest related to debt included in interest expense					5,600,000		3,500,000	11,400,000	7,000,000
Amortization of debt discount included in interest expense					16,300,000		11,800,000	32,700,000	24,200,000
Amortization of debt issuance costs					1,100,000		1,100,000	2,200,000	2,200,000
Gains (Losses) on Extinguishment of Debt							(2,700,000)		(6,100,000)
Extinguishment of Debt, Gain (Loss), Net of Tax							(1,600,000)		(3,700,000)
1.25% Convertible Senior Notes due March 2015 [Member]
Debt Instrument
Reclassification of Unamortized Debt Discount										$ 300,000
Description of Senior Notes
Aggregate Principal Amount															$ 575,000,000
Interest rate on Long-term Debt										1.25%					1.25%
Convertible debt conversion price (in dollars per share)															$ 303.06
Unamortized debt discount										$ 329,000
Debt Conversion Cash Delivered for Principal Due on Converted Debt						$ 37,500,000			$ 117,800,000
Debt Conversion, Converted Instrument, Shares Issued									289,430
Debt Conversion, Converted Instrument, Shares Issued						$ 110,100,000
Debt discount related to convertible notes, net of tax															$ 69,100,000
Debt discount related to convertible notes, before tax															115,200,000
Debt Instrument, Convertible Carrying Amount Of The Equity Component Related To Finance Costs Net Of Tax															$ 1,600,000
1.00% Convertible Senior Notes Due March 2018 [Member]
Debt Instrument
Long-term Debt					$ 936,438,000			$ 936,438,000		$ 925,166,000
Description of Senior Notes
Aggregate Principal Amount				$ 1,000,000,000
Interest rate on Long-term Debt				1.00%	1.00%			1.00%		1.00%
Debt financing costs paid												$ 20,900,000
Convertible debt conversion price (in dollars per share)				$ 944.61
Ratio of closing share price to conversion price as a condition for conversion of convertible 2015 Senior Notes, minimum				150.00%
Unamortized debt discount					$ 63,562,000			$ 63,562,000		$ 74,834,000
Effective interest rate at debt origination or modification				3.50%
Debt discount related to convertible notes, net of tax				$ 80,900,000
Debt discount related to convertible notes, before tax				135,200,000
Debt Instrument, Convertible Carrying Amount Of The Equity Component Related To Finance Costs Net Of Tax				$ 2,800,000
0.35 % Convertible Senior Notes Due June 2020 [Member]
Debt Instrument
Long-term Debt					$ 873,679,000			$ 873,679,000		$ 861,886,000
Description of Senior Notes
Aggregate Principal Amount			$ 1,000,000,000
Interest rate on Long-term Debt			0.35%		0.35%			0.35%		0.35%
Debt financing costs paid											$ 1,000,000
Convertible debt conversion price (in dollars per share)			$ 1,315.10
Ratio of closing share price to conversion price as a condition for conversion of convertible 2015 Senior Notes, minimum			150.00%
Unamortized debt discount			$ 20,000,000		$ 126,321,000			$ 126,321,000		$ 138,114,000
Effective interest rate at debt origination or modification			3.13%
Debt discount related to convertible notes, net of tax													$ 92,400,000
Debt discount related to convertible notes, before tax													154,300,000
Debt Instrument, Convertible Carrying Amount Of The Equity Component Related To Finance Costs Net Of Tax													$ 100,000
Amortization of debt discount included in interest expense					700,000		$ 700,000	1,400,000	$ 1,300,000
0.9% Convertible Senior Notes Due September 2021 [Member]
Debt Instrument
Long-term Debt					$ 873,012,000			$ 873,012,000		$ 863,701,000
Description of Senior Notes
Aggregate Principal Amount		$ 1,000,000,000
Interest rate on Long-term Debt		0.90%			0.90%			0.90%		0.90%
Debt financing costs paid										$ 11,000,000
Convertible debt conversion price (in dollars per share)		$ 2,055.50
Ratio of closing share price to conversion price as a condition for conversion of convertible 2015 Senior Notes, minimum		150.00%
Unamortized debt discount					$ 126,988,000			$ 126,988,000		136,299,000
Effective interest rate at debt origination or modification		3.18%
Debt discount related to convertible notes, net of tax										82,500,000
Debt discount related to convertible notes, before tax										142,900,000
Debt Instrument, Convertible Carrying Amount Of The Equity Component Related To Finance Costs Net Of Tax										1,600,000
Convertible Debt Liability [Member]
Description of Senior Notes
Debt, Weighted Average Interest Rate					3.40%		3.60%	3.40%	3.60%
Minimum [Member] | 1.00% Convertible Senior Notes Due March 2018 [Member]
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)				20 days
Additional Payment To Debt Holder Settled In Shares Aggregate Value Of Shares				$ 0
Minimum [Member] | 0.35 % Convertible Senior Notes Due June 2020 [Member]
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)			20 days
Additional Payment To Debt Holder Settled In Shares Aggregate Value Of Shares			$ 0
Minimum [Member] | 0.9% Convertible Senior Notes Due September 2021 [Member]
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)		20 days
Additional Payment To Debt Holder Settled In Shares Aggregate Value Of Shares		$ 0
Maximum [Member] | 1.00% Convertible Senior Notes Due March 2018 [Member]
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)				30 days
Additional Payment To Debt Holder Settled In Shares Aggregate Value Of Shares				$ 344,000,000
Maximum [Member] | 0.35 % Convertible Senior Notes Due June 2020 [Member]
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)			30 days
Additional Payment To Debt Holder Settled In Shares Aggregate Value Of Shares			$ 397,000,000
Maximum [Member] | 0.9% Convertible Senior Notes Due September 2021 [Member]
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)		30 days
Additional Payment To Debt Holder Settled In Shares Aggregate Value Of Shares		$ 375,000,000
Convertible Debt Converted Debt [Member]
Description of Senior Notes
Charge off of deferred debt issuance cost							$ 200,000		$ 500,000
Revolving Credit Facility [Member]
Debt Instrument
Revolving credit facility, maximum borrowing capacity	$ 2,000,000,000													$ 1,000,000,000
Long-term Debt					$ 0			$ 0		$ 0
Description of Senior Notes
Debt financing costs paid					3,800,000.0
Charge off of deferred debt issuance cost					$ 1,000,000
Revolving Credit Facility [Member] | Minimum [Member]
Debt Instrument
Commitment fee rate	0.085%
Revolving Credit Facility [Member] | Maximum [Member]
Debt Instrument
Commitment fee rate	0.20%
Letter of Credit [Member]
Debt Instrument
Revolving credit facility, maximum borrowing capacity	$ 70,000,000
Swingline Loans [Member]
Debt Instrument
Revolving credit facility, maximum borrowing capacity	$ 50,000,000.0
Rate 2C [Member] | Revolving Credit Facility [Member] | Minimum [Member]
Debt Instrument
Basis spread on variable rate	0.00%
Rate 2C [Member] | Revolving Credit Facility [Member] | Maximum [Member]
Debt Instrument
Basis spread on variable rate	0.50%
London Interbank Offered Rate (LIBOR) [Member] | Rate 1 [Member] | Revolving Credit Facility [Member] | Minimum [Member]
Debt Instrument
Basis spread on variable rate	0.875%
London Interbank Offered Rate (LIBOR) [Member] | Rate 1 [Member] | Revolving Credit Facility [Member] | Maximum [Member]
Debt Instrument
Basis spread on variable rate	1.50%
Federal funds rate [Member] | Rate 2B [Member] | Revolving Credit Facility [Member]
Debt Instrument
Basis spread on variable rate	0.50%
One month LIBOR [Member] | Rate 2C [Member] | Revolving Credit Facility [Member]
Debt Instrument
Basis spread on variable rate	1.00%