Income Taxes (Tables)
 12 Months Ended
Mar. 31, 2015
Income Tax Disclosure [Abstract]  
Components Of Loss Before Income Taxes
The components of our income before provision for (benefit from) income taxes for the fiscal years ended March 31, 2015, 2014 and 2013 are as follows (in millions): 
 
Year Ended March 31,
 
2015
 
2014
 
2013
Domestic
$
232

 
$
(146
)
 
$
(15
)
Foreign
693

 
153

 
154

Income before provision for (benefit from) income taxes
$
925

 
$
7

 
$
139
Provision For (Benefit From) Income Taxes
Provision for (benefit from) income taxes for the fiscal years ended March 31, 2015, 2014 and 2013 consisted of (in millions):
 
Current
 
Deferred
 
Total
Year Ended March 31, 2015
 
 
 
 
 
Federal
$
10

 
$
17

 
$
27

State
—

 
—

 
—

Foreign
21

 
2

 
23

 
$
31

 
$
19

 
$
50

Year Ended March 31, 2014
 
 
 
 
 
Federal
$
(2
)
 
$
(9
)
 
$
(11
)
State
1

 
(2
)
 
(1
)
Foreign
8

 
3

 
11

 
$
7

 
$
(8
)
 
$
(1
)
Year Ended March 31, 2013
 
 
 
 
 
Federal
$
—

 
$
5

 
$
5

State
—

 
1

 
1

Foreign
39

 
(4
)
 
35

 
$
39

 
$
2

 
$
41
Schedule Of Differences Between Statutory Tax Rate And Effective Tax Rate
The differences between the statutory tax expense rate and our effective tax expense (benefit) rate, expressed as a percentage of income before provision for (benefit from) income taxes, for the fiscal years ended March 31, 2015, 2014 and 2013 were as follows: 
 
Year Ended March 31,
 
2015
 
2014
 
2013
Statutory federal tax expense rate
35.0
 %
 
35.0
 %
 
35.0
 %
State taxes, net of federal benefit
0.1
 %
 
(242.9
)%
 
(5.0
)%
Differences between statutory rate and foreign effective tax rate
(22.3
)%
 
(142.9
)%
 
(15.2
)%
Valuation allowance
(9.2
)%
 
936.5
 %
 
35.0
 %
Research and development credits
(1.1
)%
 
(128.6
)%
 
(8.6
)%
Differences between book and tax on sale of strategic investments
—

 
—

 
(15.2
)%
Resolution of tax matters with authorities
(0.5
)%
 
(657.1
)%
 
—

Non-deductible stock-based compensation
3.5
 %
 
385.7
 %
 
21.5
 %
Acquisition-related contingent consideration
(0.2
)%
 
(185.7
)%
 
(16.5
)%
Other
0.1
 %
 
(14.3
)%
 
(1.5
)%
Effective tax expense (benefit) rate
5.4
 %
 
(14.3
)%
 
29.5
 %
Deferred Tax Assets And Liabilities
The components of net deferred tax assets, as of March 31, 2015 and 2014 consisted of (in millions): 
 
As of March 31,
 
2015
 
2014
Deferred tax assets:
 
 
 
Accruals, reserves and other expenses
$
193

 
$
163

Tax credit carryforwards
358

 
462

Stock-based compensation
35

 
43

Net operating loss & capital loss carryforwards
53

 
199

Total
639

 
867

Valuation allowance
(555
)
 
(675
)
Deferred tax assets, net of valuation allowance
84

 
192

Deferred tax liabilities:
 
 
 
Depreciation
(9
)
 
(12
)
State effect on federal taxes
(62
)
 
(63
)
Amortization
(23
)
 
(28
)
Prepaids and other liabilities
(8
)
 
(9
)
Total
(102
)
 
(112
)
Deferred tax assets, net of valuation allowance and deferred tax liabilities
$
(18
)
 
$
80
Schedule Of Unrecognized Tax Benefits
A reconciliation of the beginning and ending balance of unrecognized tax benefits is summarized as follows (in millions): 
Balance as of March 31, 2013
$
297

Increases in unrecognized tax benefits related to prior year tax positions
10

Decreases in unrecognized tax benefits related to prior year tax positions
(79
)
Increases in unrecognized tax benefits related to current year tax positions
44

Decreases in unrecognized tax benefits related to settlements with taxing authorities
(29
)
Reductions in unrecognized tax benefits due to lapse of applicable statute of limitations
(9
)
Changes in unrecognized tax benefits due to foreign currency translation
(2
)
Balance as of March 31, 2014
232

Increases in unrecognized tax benefits related to prior year tax positions
9

Decreases in unrecognized tax benefits related to prior year tax positions
(14
)
Increases in unrecognized tax benefits related to current year tax positions
50

Decreases in unrecognized tax benefits related to settlements with taxing authorities
(6
)
Reductions in unrecognized tax benefits due to lapse of applicable statute of limitations
(7
)
Changes in unrecognized tax benefits due to foreign currency translation
(10
)
Balance as of March 31, 2015
$
254