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DEBT - Debt Outstanding (Details) - USD ($)	6 Months Ended
DEBT - Debt Outstanding (Details) - USD ($)	Jun. 30, 2019	Dec. 31, 2018	Nov. 30, 2018
Debt Instrument [Line Items]
Total short-term debt	$ 1,349,000,000	$ 1,694,000,000
Long-term debt	4,377,000,000	4,375,000,000
Commercial paper
Debt Instrument [Line Items]
Short-term debt	300,000,000	645,000,000
Term note
Debt Instrument [Line Items]
Short-term debt	$ 650,000,000	650,000,000
Face amount			$ 1,000,000,000.0
Senior notes
Debt Instrument [Line Items]
Redemption price, percentage	100.00%
Senior notes \| $400 million, 2.625% due October 1, 2019
Debt Instrument [Line Items]
Long-term debt, current maturities	$ 399,000,000	399,000,000
Stated interest rate	2.625%
Face amount	$ 400,000,000
Senior notes \| $400 million, 2.50% due December 15, 2020
Debt Instrument [Line Items]
Long-term debt	$ 399,000,000	398,000,000
Stated interest rate	2.50%
Face amount	$ 400,000,000
Senior notes \| $400 million, 2.90% due December 15, 2022
Debt Instrument [Line Items]
Long-term debt	$ 397,000,000	396,000,000
Stated interest rate	2.90%
Face amount	$ 400,000,000
Senior notes \| $600 million, 3.15% due December 1, 2022
Debt Instrument [Line Items]
Long-term debt	$ 597,000,000	596,000,000
Stated interest rate	3.15%
Face amount	$ 600,000,000
Senior notes \| $600 million, 3.85% due October 1, 2024
Debt Instrument [Line Items]
Long-term debt	$ 597,000,000	597,000,000
Stated interest rate	3.85%
Face amount	$ 600,000,000
Senior notes \| $600 million, 3.95% due March 15, 2027
Debt Instrument [Line Items]
Long-term debt	$ 595,000,000	594,000,000
Stated interest rate	3.95%
Face amount	$ 600,000,000
Senior notes \| $250 million, 8.15% due June 15, 2038
Debt Instrument [Line Items]
Long-term debt	$ 262,000,000	263,000,000
Stated interest rate	8.15%
Face amount	$ 250,000,000
Senior notes \| $400 million, 4.625% due December 1, 2042
Debt Instrument [Line Items]
Long-term debt	$ 396,000,000	396,000,000
Stated interest rate	4.625%
Face amount	$ 400,000,000
Senior notes \| $750 million, 4.95% due October 1, 2044
Debt Instrument [Line Items]
Long-term debt	$ 739,000,000	739,000,000
Stated interest rate	4.95%
Face amount	$ 750,000,000
Senior notes \| $400 million, 4.80% due March 15, 2047
Debt Instrument [Line Items]
Long-term debt	$ 395,000,000	$ 396,000,000
Stated interest rate	4.80%
Face amount	$ 400,000,000