Income Taxes 4 (Details) - USD ($) $ in Millions	Mar. 31, 2018	Mar. 31, 2017
Deferred tax assets:
Modified accrual basis accounting for revenue	$ 283	$ 364
Share-based compensation	31	41
Accrued expenses	12	11
Net operating losses	125	149
Total deferred tax assets	512	646
Valuation allowance	(72)	(89)
Total deferred tax assets, net of valuation allowance	440	557
Deferred tax liabilities:
Depreciation	0	3
Other intangible assets	70	116
Total deferred tax liabilities	204	349
Net deferred tax asset	236	208
Deductible State Tax and Interest Benefits
Deferred tax assets:
Deferred tax assets, Other	10	19
Other
Deferred tax assets:
Deferred tax assets, Other	51	62
Purchased Software
Deferred tax liabilities:
Capitalized software	129	207
Internally Developed Software
Deferred tax liabilities:
Capitalized software	$ 5	$ 23