Income Taxes (Tables)

12 Months Ended

Mar. 31, 2016

Income Tax Disclosure [Abstract]

Schedule of income from continuing operations before income taxes

	Years Ended March 31,
(In millions)	2016		2015		2014
Income from continuing operations before income taxes
U.S.	$	2,319	$	1,893	$	1,554
Foreign	931		764		617
Total income from continuing operations before income taxes	$	3,250	$	2,657	$	2,171

Schedule of income tax expense related to continuing operations

Income tax expense related to continuing operations consists of the following:

	Years Ended March 31,
(In millions)	2016			2015			2014
Current
Federal	$	658		$	453		$	484
State	96			90			64
Foreign	90			101			193
Total current	844			644			741
Deferred
Federal	95			195			24
State	42			53			10
Foreign	(73		)	(77		)	(18		)
Total deferred	64			171			16
Income tax expense	$	908		$	815		$	757

Schedule of reconciliation between effective tax rate on income from continuing operations and statutory tax rate

The reconciliation between our effective tax rate on income from continuing operations and statutory tax rate is as follows:

	Years Ended March 31,
(In millions)	2016			2015			2014
Income tax expense at federal statutory rate	$	1,137		$	930		$	760
State income taxes net of federal tax benefit	92			81			57
Foreign income taxed at various rates	(295		)	(247		)	(177		)
Canadian litigation	(8		)	—			122
Controlled substance distribution reserve	—			58			—
Unrecognized tax benefits and settlements	(6		)	10			(6		)
Tax credits	(18		)	(10		)	(6		)
Other, net	6			(7		)	7
Income tax expense	$	908		$	815		$	757

Schedule of deferred tax balances

Deferred tax balances consisted of the following:

	March 31,
(In millions)	2016			2015
Assets
Receivable allowances	$	110		$	83
Deferred revenue	77			72
Compensation and benefit related accruals	710			681
Net operating loss and credit carryforwards	367			316
Other	275			266
Subtotal	1,539			1,418
Less: valuation allowance	(267		)	(229		)
Total assets	1,272			1,189
Liabilities
Inventory valuation and other assets	(2,619		)	(2,333		)
Fixed assets and systems development costs	(326		)	(324		)
Intangibles	(981		)	(1,073		)
Other	(21		)	(61		)
Total liabilities	(3,947		)	(3,791		)
Net deferred tax liability	$	(2,675	)	$	(2,602	)
Current net deferred tax asset (1)	$	—		$	27
Current net deferred tax liability (1)	—			(1,820		)
Long-term deferred tax asset	59			50
Long-term deferred tax liability	(2,734		)	(859		)
Net deferred tax liability	$	(2,675	)	$	(2,602	)

(1) Upon the adoption of the amended accounting guidance, we reclassified current net deferred tax liabilities and current net deferred tax assets as noncurrent on our consolidated balance sheet as of March 31, 2016. Our March 31, 2015 balances were not retrospectively reclassified.

Schedule of gross unrecognized tax benefits

The following table summarizes the activity related to our gross unrecognized tax benefits for the last three years:

	Years Ended March 31,
(In millions)	2016			2015			2014
Unrecognized tax benefits at beginning of period	$	616		$	647		$	560
Additions based on tax positions related to prior years	116			62			106
Reductions based on tax positions related to prior years	(62		)	(18		)	(23		)
Additions based on tax positions related to current year	28			27			23
Reductions based on settlements	(141		)	(65		)	(4		)
Reductions based on the lapse of the applicable statutes of limitations	(6		)	(12		)	(7		)
Exchange rate fluctuations	4			(25		)	(8		)
Unrecognized tax benefits at end of period	$	555		$	616		$	647