USE OF DERIVATIVES, OFFSETTING DISCLOSURES AND CHANGES IN OTHER COMPREHENSIVE INCOME BY COMPONENT - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2019	Sep. 30, 2016
Derivative Instruments And Hedging Activities Disclosures [Line Items]
SWAP agreement notional amount during period	$ 2,600	$ 100
SWAP agreement average interest rate during period	2.55%	4.09%
Swap agreement notional amount expiring during period	$ 950
SWAP agreement average interest rate expiring during period	1.58%
Interest Rate Swap Agreements [Member]
Derivative Instruments And Hedging Activities Disclosures [Line Items]
Payment term of LIBOR interest rate agreement	20 years
Interest Rate Swap Agreements [Member] | Minimum [Member]
Derivative Instruments And Hedging Activities Disclosures [Line Items]
Payment term of LIBOR interest rate agreement	2 years
Interest Rate Swap Agreements [Member] | Maximum [Member]
Derivative Instruments And Hedging Activities Disclosures [Line Items]
Payment term of LIBOR interest rate agreement	3 years