Segment Information 1 (Details) - USD ($) $ in Millions	3 Months Ended				6 Months Ended
	Sep. 30, 2015		Sep. 30, 2014		Sep. 30, 2015		Sep. 30, 2014
Segment information
Revenue	$ 1,005		$ 1,079		$ 1,982		$ 2,148
Income from continuing operations before interest and income taxes	259		320		563		633
Reconciliation of segment profit to income from continuing operations before income taxes
Segment profit	259		320		563		633
Share-based compensation expense	23		22		45		42
Other (gains) expenses, net	(6)	[1]	(4)	[2]	2	[3]	8	[4]
Interest expense, net	12		12		21		26
Income from continuing operations before income taxes	247		308		542		607
Purchased Software Products
Reconciliation of segment profit to income from continuing operations before income taxes
Amortization of intangible assets	39		31		67		59
Other Intangible Assets
Reconciliation of segment profit to income from continuing operations before income taxes
Amortization of intangible assets	14		16		25		31
Internally Developed Software Products
Reconciliation of segment profit to income from continuing operations before income taxes
Amortization of intangible assets	28		44		60		83
Mainframe Solutions
Segment information
Revenue	554		610		1,114		1,224
Expenses	212		234		423		469
Income from continuing operations before interest and income taxes	$ 342		$ 376		$ 691		$ 755
Segment operating margin	62.00%		62.00%		62.00%		62.00%
Depreciation	$ 9		$ 11		$ 18		$ 23
Reconciliation of segment profit to income from continuing operations before income taxes
Segment profit	342		376		691		755
Enterprise Solutions
Segment information
Revenue	368		378		706		746
Expenses	357		327		647		652
Income from continuing operations before interest and income taxes	$ 11		$ 51		$ 59		$ 94
Segment operating margin	3.00%		13.00%		8.00%		13.00%
Depreciation	$ 6		$ 7		$ 13		$ 14
Reconciliation of segment profit to income from continuing operations before income taxes
Segment profit	11		51		59		94
Services
Segment information
Revenue	83		91		162		178
Expenses	79		89		150		171
Income from continuing operations before interest and income taxes	$ 4		$ 2		$ 12		$ 7
Segment operating margin	5.00%		2.00%		7.00%		4.00%
Depreciation	$ 0		$ 0		$ 0		$ 0
Reconciliation of segment profit to income from continuing operations before income taxes
Segment profit	4		2		12		7
Total Reportable Segments
Segment information
Revenue	1,005		1,079		1,982		2,148
Expenses	648		650		1,220		1,292
Income from continuing operations before interest and income taxes	$ 357		$ 429		$ 762		$ 856
Segment operating margin	36.00%		40.00%		38.00%		40.00%
Depreciation	$ 15		$ 18		$ 31		$ 37
Reconciliation of segment profit to income from continuing operations before income taxes
Segment profit	$ 357		$ 429		$ 762		$ 856

[1] Other gains, net consists of costs associated with certain foreign exchange derivative hedging gains and losses, and other miscellaneous costs.

[2] Other gains, net consists of costs associated with the Fiscal 2014 Plan, certain foreign exchange derivative hedging gains and losses, and other miscellaneous costs.

[3] Other expenses, net consists of costs associated with certain foreign exchange derivative hedging gains and losses, and other miscellaneous costs.

[4] Other expenses, net consists of costs associated with the Fiscal 2014 Plan, certain foreign exchange derivative hedging gains and losses, and other miscellaneous costs.