Goodwill, Capitalized Software and Other Intangible Assets 1 (Details) - USD ($) $ in Millions	Sep. 30, 2018	Mar. 31, 2018
Capitalized software and other intangible assets
Gross amortizable assets	$ 9,261	$ 9,265
Less: Fully amortized assets	7,539	7,131
Remaining amortizable assets	1,722	2,134
Accumulated amortization on remaining amortizable assets	741	1,023
Net assets	981	1,111
Purchased Software Products
Capitalized software and other intangible assets
Gross amortizable assets	6,579	6,572
Less: Fully amortized assets	5,247	4,961
Remaining amortizable assets	1,332	1,611
Accumulated amortization on remaining amortizable assets	658	845
Net assets	674	766
Internally Developed Software Products
Capitalized software and other intangible assets
Gross amortizable assets	1,467	1,467
Less: Fully amortized assets	1,458	1,347
Remaining amortizable assets	9	120
Accumulated amortization on remaining amortizable assets	6	109
Net assets	3	11
Other Intangible Assets
Capitalized software and other intangible assets
Gross amortizable assets	1,215	1,226
Less: Fully amortized assets	834	823
Remaining amortizable assets	381	403
Accumulated amortization on remaining amortizable assets	77	69
Net assets	$ 304	$ 334