Income Taxes - Components Of Deferred Tax Balances (Details) - USD ($) $ in Millions	Mar. 31, 2017	Mar. 31, 2016
Assets
Receivable allowances	$ 124	$ 110
Deferred revenue	19	77
Compensation and benefit related accruals	593	710
Net operating loss and credit carryforwards	594	367
Long-term contractual obligations	107	0
Other	222	275
Subtotal	1,659	1,539
Less: valuation allowance	(503)	(267)
Total assets	1,156	1,272
Liabilities
Inventory valuation and other assets	(2,818)	(2,619)
Fixed assets and systems development costs	(224)	(326)
Intangibles	(921)	(981)
Change Healthcare Equity Investment	(773)	0
Other	(70)	(21)
Total liabilities	(4,806)	(3,947)
Net deferred tax liability	(3,650)	(2,675)
Long-term deferred tax asset	28	59
Long-term deferred tax liability	$ (3,678)	$ (2,734)