SHARE-BASED COMPENSATION - Other Equity Awards Activity (Details) - $ / shares	12 Months Ended
Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Share bonus awards
Option Activity
Unvested share bonus targeted number of awards, beginning of period (in shares)	14,619,692	17,242,019	19,309,172
Granted (in shares)	8,257,502	6,680,739	8,261,666
Vested (in shares)	(5,952,039)	(6,945,393)	(9,311,984)
Forfeited (in shares)	(2,021,269)	(2,357,673)	(1,016,835)
Unvested share bonus targeted number of awards, end of period (in shares)	14,903,886	14,619,692	17,242,019
Price Per Share
Unvested share bonus awards, weighted average grant-date fair value, end of period (in dollars per share)	$ 14.39	$ 12.24	$ 10.71
Average grant date fair value (per share)	12.59	16.97	13.46
Vested, weighted average grant-date fair value (in dollars per share)	13.12	11.86	9.50
Forfeited, weighted average grant-date fair value (in dollars per share)	14.51	12.20	11.15
Unvested share bonus awards, weighted average grant-date fair value, end of period (in dollars per share)	$ 13.76	$ 14.39	$ 12.24
Share Bonus Awards with Market Conditions
Option Activity
Unvested share bonus targeted number of awards, end of period (in shares)	2,521,930
Share Bonus Awards with Market Conditions \| Fiscal 2017
Option Activity
Granted (in shares)	700,000.0	1,700,000.0
Unvested share bonus targeted number of awards, end of period (in shares)	586,077
Price Per Share
Average grant date fair value (per share)	$ 20.25

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The number of equity-based payment instruments, excluding stock (or unit) options, that were forfeited during the reporting period.

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Weighted average fair value as of the grant date of equity-based award plans other than stock (unit) option plans that were not exercised or put into effect as a result of the occurrence of a terminating event.

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The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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The weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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The number of non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date.

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The weighted average fair value of nonvested awards on equity-based plans excluding option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, revenue or profit achievement stock award plan) for which the employer is contingently obligated to issue equity instruments or transfer assets to an employee who has not yet satisfied service or performance criteria necessary to gain title to proceeds from the sale of the award or underlying shares or units.

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The number of equity-based payment instruments, excluding stock (or unit) options, that vested during the reporting period.

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The weighted average fair value as of grant date pertaining to an equity-based award plan other than a stock (or unit) option plan for which the grantee gained the right during the reporting period, by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash in accordance with the terms of the arrangement.

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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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