Fair Value Measurements (Fair Value Measurements Using Significant Unobservable Inputs (Level 3)) (Details) - USD ($) $ in Millions	12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Change in fair value	$ 14
Other Liabilities [Member] | Significant Unobservable Inputs (Level 3) [Member] | Contingent Consideration [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value, Contingent consideration	136	$ 122	[1]
Respawn Entertainment, LLC [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Change in fair value	14
Respawn Entertainment, LLC [Member] | Contingent Consideration [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value, Contingent consideration	$ 136	$ 0

[1] The contingent consideration represents the estimated fair value of the additional variable cash consideration payable in connection with our acquisition of Respawn Entertainment, LLC (“Respawn”) that is contingent upon the achievement of certain performance milestones. We estimated fair value using a probability-weighted income approach combined with a real options methodology, and applied a discount rate that appropriately captures the risk associated with the obligation. At March 31, 2019, the discount rates used ranged from 2.9 percent to 3.1 percent. See Note 7 for additional information regarding the Respawn acquisition. At March 31, 2018, the discount rates used ranged from 3.3 percent to 3.6 percent.