Long-Lived Assets 5 (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Goodwill activity by segment
Balance at beginning of year	$ 5,864	$ 5,856
Acquisitions	55	10
Foreign currency translation adjustment	3	(2)
Balance at end of year	5,922	5,864
Mainframe Solutions [Member]
Goodwill activity by segment
Balance at beginning of year	4,178	4,179
Acquisitions	0	0
Foreign currency translation adjustment	0	(1)
Balance at end of year	4,178	4,178
Enterprise Solutions [Member]
Goodwill activity by segment
Balance at beginning of year	1,605	1,596
Acquisitions	55	10
Foreign currency translation adjustment	3	(1)
Balance at end of year	1,663	1,605
Services [Member]
Goodwill activity by segment
Balance at beginning of year	81	81
Acquisitions	0	0
Foreign currency translation adjustment	0	0
Balance at end of year	$ 81	$ 81