Revenue from Contracts with Customers 3 (Details) $ in Millions	6 Months Ended
	Sep. 30, 2018 USD ($)
Period between Two and Three Years
Transaction price allocated to remaining performance obligations
Remaining performance obligations	$ 1,700
Period between Two and Three Years | Minimum
Transaction price allocated to remaining performance obligations
Period of performance obligations greater than 12 months	2 years
Period between Two and Three Years | Maximum
Transaction price allocated to remaining performance obligations
Period of performance obligations greater than 12 months	3 years
Period between Four and Five Years | Minimum
Transaction price allocated to remaining performance obligations
Period of performance obligations greater than 12 months	4 years
Period between Four and Five Years | Maximum
Transaction price allocated to remaining performance obligations
Period of performance obligations greater than 12 months	5 years
Perpetual Licenses | 12 Months or Less
Transaction price allocated to remaining performance obligations
Remaining performance obligations	$ 10
Perpetual Licenses | Greater than 12 Months
Transaction price allocated to remaining performance obligations
Remaining performance obligations	11	[1]
On-Premise Term Licenses | 12 Months or Less
Transaction price allocated to remaining performance obligations
Remaining performance obligations	231
On-Premise Term Licenses | Greater than 12 Months
Transaction price allocated to remaining performance obligations
Remaining performance obligations	113	[1]
Maintenance | 12 Months or Less
Transaction price allocated to remaining performance obligations
Remaining performance obligations	1,464
Maintenance | Greater than 12 Months
Transaction price allocated to remaining performance obligations
Remaining performance obligations	1,632	[1]
SaaS | 12 Months or Less
Transaction price allocated to remaining performance obligations
Remaining performance obligations	345
SaaS | Greater than 12 Months
Transaction price allocated to remaining performance obligations
Remaining performance obligations	221	[1]
Professional Services | 12 Months or Less
Transaction price allocated to remaining performance obligations
Remaining performance obligations	61
Professional Services | Greater than 12 Months
Transaction price allocated to remaining performance obligations
Remaining performance obligations	31	[1]
Material Rights | 12 Months or Less
Transaction price allocated to remaining performance obligations
Remaining performance obligations	3
Material Rights | Greater than 12 Months
Transaction price allocated to remaining performance obligations
Remaining performance obligations	$ 178	[1]

[1] Of the amount of performance obligations greater than 12 months, the portion that is 2 to 3 years is approximately $1.7 billion and the remaining amount is generally between 4 and 5 years.