Goodwill, Capitalized Software and Other Intangible Assets 1 (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2012	Mar. 31, 2012
Capitalized software and other intangible assets
Gross amortizable assets	$ 7,951	$ 7,808
Less: Fully amortized assets	5,807	5,719
Remaining amortizable assets	2,144	2,089
Accumulated amortization on remaining amortizable assets	848	700
Net assets	1,296	1,389
Purchased Software Products [Member]
Capitalized software and other intangible assets
Gross amortizable assets	5,651	5,628
Less: Fully amortized assets	4,740	4,733
Remaining amortizable assets	911	895
Accumulated amortization on remaining amortizable assets	301	228
Net assets	610	667
Internally Developed Software Products [Member]
Capitalized software and other intangible assets
Gross amortizable assets	1,487	1,366
Less: Fully amortized assets	638	574
Remaining amortizable assets	849	792
Accumulated amortization on remaining amortizable assets	310	258
Net assets	539	534
Other Intangible Assets [Member]
Capitalized software and other intangible assets
Gross amortizable assets	813	814
Less: Fully amortized assets	429	412
Remaining amortizable assets	384	402
Accumulated amortization on remaining amortizable assets	237	214
Net assets	$ 147	$ 188