Segment Information 2 (Details) - USD ($) $ in Millions		3 Months Ended
		Jun. 30, 2018		Jun. 30, 2017
Summary of segment profit and reconciliation to income before income taxes
Total segment profit		$ 430		$ 383
Impact of segment policies that differ from U.S. GAAP		(117)	[1]	0
Share-based compensation expense		33		32
Other expenses, net	[2]	108		8
Interest expense, net		20		25
Income before income taxes		82		238
Purchased Software Products
Summary of segment profit and reconciliation to income before income taxes
Amortization of intangible assets		55		58
Other Intangible Assets
Summary of segment profit and reconciliation to income before income taxes
Amortization of intangible assets		10		10
Internally Developed Software Products
Summary of segment profit and reconciliation to income before income taxes
Amortization of intangible assets		5		12
Mainframe Solutions
Summary of segment profit and reconciliation to income before income taxes
Total segment profit		370		349
Enterprise Solutions
Summary of segment profit and reconciliation to income before income taxes
Total segment profit		60		33
Services
Summary of segment profit and reconciliation to income before income taxes
Total segment profit		$ 0		$ 1

[1] The manner in which the Company measures and recognizes revenues and expenses, including commissions, for segment reporting was not revised upon adoption of Topic 606. For segment reporting purposes, commissions are expensed in the period earned by the employee.

[2] Other expenses, net for the three months ended June 30, 2018 consisted of costs associated with the Fiscal 2019 Plan of $114 million, certain foreign exchange derivative hedging gains and losses, and other miscellaneous costs. Other expenses, net for the three months ended June 30, 2017 consisted of costs associated with certain foreign exchange derivative hedging gains and losses, and other miscellaneous costs.