Stockholders' Equity (Other Comprehensive Income (Loss), Net of Tax) (Parentheticals) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013	Dec. 31, 2012
Stockholders' Equity Attributable to Parent [Abstract]
Foreign currency translation adjustments arising during period, income tax expense (benefit) of nil, ($4), nil and ($2)	$ 0	$ (4)	$ 0	$ (2)
Reclassified to income statement, income tax expense of nil, nil, $24 and nil	0	0	24	0
Unrealized gains (losses) on cash flow hedges arising during period, income tax expense of nil, nil, nil and nil	0	0	0	0
Amortization of actuarial loss, prior service cost and transition obligation, income tax expense of $4, $3, $10 and $8	4	3	10	8
Foreign currency translation adjustments, income tax expense of nil, nil, nil and nil	0	0	0	0
Reclassified to income statement, income tax expense of nil, nil, $1 and nil	$ 0	$ 0	$ 1	$ 0