DEBT, CREDIT FACILITIES AND LEASE COMMITMENTS - Schedule of Debt (Details) - USD ($) $ in Millions	Dec. 31, 2019	Jun. 30, 2019	May 31, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	May 31, 2017
Debt Instrument [Line Items]
Debt and capital lease obligations	$ 5,124				$ 3,483
Current portion	(315)	$ (2)		$ (2)	(2)	$ (3)	$ (3)	$ (3)
Long-term debt and finance lease obligations	$ 4,809	$ 5,157		$ 3,451	3,481	$ 3,480	$ 3,491	$ 3,550
Variable-rate loan due 2020
Debt Instrument [Line Items]
Effective Interest Rate	1.00%
Debt and capital lease obligations	$ 313				310
1.7% notes due 2021
Debt Instrument [Line Items]
Senior notes, coupon rates	1.70%
Effective Interest Rate	1.90%
Debt and capital lease obligations	$ 398				398
2.4% notes due 2022
Debt Instrument [Line Items]
Senior notes, coupon rates	2.40%
Effective Interest Rate	2.50%
Debt and capital lease obligations	$ 203				202
0.40% notes due 2024
Debt Instrument [Line Items]
Senior notes, coupon rates	0.40%								0.40%
Effective Interest Rate	0.60%
Debt and capital lease obligations	$ 834				0
1.3% notes due 2025
Debt Instrument [Line Items]
Senior notes, coupon rates	1.30%
Effective Interest Rate	1.40%
Debt and capital lease obligations	$ 669				684
2.6% notes due 2026
Debt Instrument [Line Items]
Senior notes, coupon rates	2.60%
Effective Interest Rate	2.70%
Debt and capital lease obligations	$ 746				745
7.65% Debentures due 2027
Debt Instrument [Line Items]
Senior notes, coupon rates	7.65%
Effective Interest Rate	7.70%
Debt and capital lease obligations	$ 5				5
6.625% Debentures due 2028
Debt Instrument [Line Items]
Senior notes, coupon rates	6.625%
Effective Interest Rate	6.70%
Debt and capital lease obligations	$ 98				98
1.3% notes due 2029
Debt Instrument [Line Items]
Senior notes, coupon rates	1.30%		1.30%
Effective Interest Rate	1.30%
Debt and capital lease obligations	$ 830				0
6.25% notes due 2037
Debt Instrument [Line Items]
Senior notes, coupon rates	6.25%
Effective Interest Rate	6.30%
Debt and capital lease obligations	$ 265				265
3.65% Notes due 2042
Debt Instrument [Line Items]
Senior notes, coupon rates	3.65%
Effective Interest Rate	3.70%
Debt and capital lease obligations	$ 6				6
4.5% notes due 2043
Debt Instrument [Line Items]
Senior notes, coupon rates	4.50%
Effective Interest Rate	4.50%
Debt and capital lease obligations	$ 255				255
3.5% notes due 2046
Debt Instrument [Line Items]
Senior notes, coupon rates	3.50%
Effective Interest Rate	3.60%
Debt and capital lease obligations	$ 440				439
Finance leases and other
Debt Instrument [Line Items]
Effective Interest Rate	10.00%
Debt and capital lease obligations	$ 62				$ 76