CONDENSED CONSOLIDATED COMBINED BALANCE SHEETS (Parenthetical) - USD ($) $ in Millions	Sep. 30, 2018	Mar. 31, 2018	Mar. 31, 2017
Current assets:
Allowance for doubtful accounts	$ 2	$ 0
Intangible and other assets:
Accumulated amortization	181	98
Accumulated depreciation and amortization	$ 100	$ 66
Equity
Common stock, par value (in dollars per share)	$ 0.01
Common stock, authorized (in shares)	750,000,000
Common stock, issued (in shares)	164,818,944
Common stock, outstanding (in shares)	0
Treasury stock (in shares)	938,287		0

Intangible And Other Assets [Abstract]

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Amount of accumulated depreciation, depletion and amortization for physical assets used in the normal conduct of business to produce goods and services.

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A valuation allowance for trade and other receivables due to an Entity within one year (or the normal operating cycle, whichever is longer) that are expected to be uncollectible.

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Face amount or stated value per share of common stock.

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The maximum number of common shares permitted to be issued by an entity's charter and bylaws.

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Total number of common shares of an entity that have been sold or granted to shareholders (includes common shares that were issued, repurchased and remain in the treasury). These shares represent capital invested by the firm's shareholders and owners, and may be all or only a portion of the number of shares authorized. Shares issued include shares outstanding and shares held in the treasury.

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Number of shares of common stock outstanding. Common stock represent the ownership interest in a corporation.

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Accumulated amount of amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

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Number of previously issued common shares repurchased by the issuing entity and held in treasury.

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