Long-Lived Assets 3 (Details) - USD ($) $ in Millions	12 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2016
Depreciation and amortization expense
Depreciation	$ 66	$ 58	$ 62
Total depreciation and amortization expense	378	320	362
Purchased Software Products
Depreciation and amortization expense
Amortization of intangible assets	235	164	146
Internally Developed Software Products
Depreciation and amortization expense
Amortization of intangible assets	36	79	110
Other Intangible Assets
Depreciation and amortization expense
Amortization of intangible assets	$ 41	$ 19	$ 44