Income Taxes (Provision For (Benefit From) Income Taxes) (Details) (USD $)
In Millions, unless otherwise specified
12 Months Ended
Mar. 31, 2015
Mar. 31, 2014
Mar. 31, 2013
Income Tax Disclosure [Abstract]      
Federal, Current $ 10 $ (2) $ 0
State, Current 0 1 0
Foreign, Current 21 8 39
Total, Current 31 7 39
Federal, Deferred 17 (9) 5
State, Deferred 0 (2) 1
Foreign, Deferred 2 3 (4)
Total, Deferred 19 (8) 2
Total, Federal 27 (11) 5
Total, State 0 (1) 1
Total, Foreign 23 11 35
Total provision for (benefit from) income taxes $ 50 $ (1) $ 41