DEBT (Outstanding Debt) (Details) $ / shares in Units, $ in Millions		1 Months Ended	3 Months Ended		12 Months Ended
	Aug. 20, 2014 USD ($) Days $ / shares	May 31, 2013 USD ($) Days $ / shares	Mar. 31, 2019 USD ($)	Mar. 31, 2018 USD ($)	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)	Mar. 31, 2019 EUR (€)	Dec. 31, 2018 USD ($)	Dec. 31, 2018 EUR (€)	Aug. 15, 2017	Mar. 10, 2017	May 23, 2016	Nov. 25, 2015	Mar. 13, 2015	Mar. 03, 2015	Sep. 23, 2014	Jun. 30, 2013 USD ($)	Mar. 31, 2012 USD ($) $ / shares
Debt Instrument
Outstanding Principal Amount, Long-term debt			$ 7,711					$ 8,787
Unamortized Debt Discount and Debt Issuance Cost			(92)					(138)
Carrying Value, Long-term debt			7,619					8,649
Description of Senior Notes
Payments Related to Conversion of Senior Notes			0	$ 1,487
0.35% Convertible Senior Notes due June 2020
Debt Instrument
Short-term Debt, Gross			1,000
Carrying Value, Short-term debt			968
Outstanding Principal Amount, Long-term debt								1,000
Unamortized Debt Discount and Debt Issuance Cost			$ (32)					(39)
Carrying Value, Long-term debt								$ 961
Description of Senior Notes
Aggregate principal amount		$ 1,000
Interest rate on Long-term Debt		0.35%	0.35%				0.35%	0.35%	0.35%
Debt financing costs paid						$ 1
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
Effective interest rate at debt origination or modification		3.125%
Debt discount related to convertible notes, net of tax																	$ 92
Debt discount related to convertible notes, before tax																	$ 154
Amortization of debt discount included in interest expense			$ 1	1
0.9% Convertible Senior Notes due September 2021
Debt Instrument
Outstanding Principal Amount, Long-term debt			1,000					$ 1,000
Unamortized Debt Discount and Debt Issuance Cost			(56)					(61)
Carrying Value, Long-term debt			$ 944					$ 939
Description of Senior Notes
Aggregate principal amount	$ 1,000
Interest rate on Long-term Debt	0.90%		0.90%				0.90%	0.90%	0.90%
Debt financing costs paid					$ 11
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					83
Debt discount related to convertible notes, before tax					$ 143
0.8% (€1 Billion) Senior Notes due March 2022
Debt Instrument
Outstanding Principal Amount, Long-term debt			$ 1,123					$ 1,143
Unamortized Debt Discount and Debt Issuance Cost			(4)					(5)
Carrying Value, Long-term debt			$ 1,119					$ 1,138
Description of Senior Notes
Aggregate principal amount | €							€ 1,000,000,000		€ 1,000,000,000
Interest rate on Long-term Debt			0.80%				0.80%	0.80%	0.80%
Effective interest rate at debt origination or modification											0.842%
2.15% (€750 Million) Senior Notes due November 2022
Debt Instrument
Outstanding Principal Amount, Long-term debt			$ 842					$ 858
Unamortized Debt Discount and Debt Issuance Cost			(3)					(4)
Carrying Value, Long-term debt			$ 839					$ 854
Description of Senior Notes
Aggregate principal amount | €							€ 750,000,000		€ 750,000,000
Interest rate on Long-term Debt			2.15%				2.15%	2.15%	2.15%
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					$ 500
Unamortized Debt Discount and Debt Issuance Cost			(3)					(3)
Carrying Value, Long-term debt			$ 497					$ 497
Description of Senior Notes
Interest rate on Long-term Debt			2.75%				2.75%	2.75%	2.75%
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			$ 1,123					$ 1,143
Unamortized Debt Discount and Debt Issuance Cost			(10)					(10)
Carrying Value, Long-term debt			$ 1,113					$ 1,133
Description of Senior Notes
Aggregate principal amount | €							€ 1,000,000,000		€ 1,000,000,000
Interest rate on Long-term Debt			2.375%				2.375%	2.375%	2.375%
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					$ 500
Unamortized Debt Discount and Debt Issuance Cost			(3)					(3)
Carrying Value, Long-term debt			$ 497					$ 497
Description of Senior Notes
Interest rate on Long-term Debt			3.65%				3.65%	3.65%	3.65%
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					$ 1,000
Unamortized Debt Discount and Debt Issuance Cost			(6)					(6)
Carrying Value, Long-term debt			$ 994					$ 994
Description of Senior Notes
Interest rate on Long-term Debt			3.60%				3.60%	3.60%	3.60%
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			$ 1,123					$ 1,143
Unamortized Debt Discount and Debt Issuance Cost			(4)					(4)
Carrying Value, Long-term debt			$ 1,119					$ 1,139
Description of Senior Notes
Aggregate principal amount | €							€ 1,000,000,000		€ 1,000,000,000
Interest rate on Long-term Debt			1.80%				1.80%	1.80%	1.80%
Effective interest rate at debt origination or modification															1.803%
3.55% Senior Notes due March 2028
Debt Instrument
Outstanding Principal Amount, Long-term debt			$ 500					$ 500
Unamortized Debt Discount and Debt Issuance Cost			(3)					(3)
Carrying Value, Long-term debt			$ 497					$ 497
Description of Senior Notes
Interest rate on Long-term Debt			3.55%				3.55%	3.55%	3.55%
Effective interest rate at debt origination or modification										3.56%
1.0% Convertible Senior Notes due March 2018
Description of Senior Notes
Aggregate principal amount																		$ 1,000
Interest rate on Long-term Debt																		1.00%
Convertible debt conversion price (in dollars per share) | $ / shares																		$ 944.61
Payments Related to Conversion of Senior Notes			$ 714
Debt Conversion, Converted Instrument, Cash			773
Effective interest rate at debt origination or modification																		3.50%
Debt discount related to convertible notes, net of tax																		$ 81
Debt discount related to convertible notes, before tax																		$ 135
Convertible Debt
Description of Senior Notes
Interest expense related to debt			15	20
Coupon Interest expense			3	5
Amortization of debt discount included in interest expense			$ 12	$ 14
Debt, weighted average interest rate			3.20%	3.30%
Other Long-term Debt
Debt Instrument
Carrying Value, Long-term debt			$ 6,700					$ 6,700
Description of Senior Notes
Interest expense related to debt			42	$ 43
Coupon Interest expense			40	$ 42
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
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
Level 2
Description of Senior Notes
Estimated market value of outstanding debt			$ 9,500					$ 9,300