Stockholders' Equity (Changes in Accumulated Other Comprehensive Income (Loss) by Component) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended				6 Months Ended
	Sep. 30, 2013		Sep. 30, 2012		Sep. 30, 2013		Sep. 30, 2012
Stockholders' Equity Attributable to Parent [Abstract]
Foreign Currency Translation Adjustments, Net of Tax, Beginning Balance					$ 136
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Gain (Loss) Arising During Period, Net of Tax	56		71		(5)		30
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Reclassification Adjustment from AOCI, Realized upon Sale or Liquidation, Net of Tax	44	[1]	0	[1]	44	[1]	0	[1]
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax	100		71		39		30
Foreign Currency Translation Adjustments, Net of Tax, Ending Balance	175				175
Unrealized Losses on Cash Flow Hedges, Net of Tax, Beginning Balance					(5)
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Net of Tax	(2)		2		(1)		2
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, Net of Tax					0
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax	(2)		2		(1)		2
Unrealized Losses on Cash Flow Hedges, Net of Tax, Ending Balance	(6)				(6)
Unrealized Net Loss and Other Components of Benefit Plans, Net of Tax, Beginning Balance					(196)
Other Comprehensive Income Translation Impact On Pension Plans, Net Of Tax	(3)		(1)		(3)		0
Other Comprehensive (Income) Loss, Total Reclassification Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, Net of Tax					14
Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax	4		3		11		9
Unrealized Net Loss and Other Components of Benefit Plans, Net of Tax, Ending Balance	(185)				(185)
Total Accumulated Other Comprehensive Income (Loss), Beginning Balance					(65)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax					(9)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax					58
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	102		76		49		41
Total Accumulated Other Comprehensive Income (Loss), Ending Balance	$ (16)				$ (16)

[1] As a result of our sale of our 49% equity interest in Nadro, foreign currency translation net losses of $44 million were reclassified from AOCI to other income, within our condensed consolidated statement of operations. Such losses were previously considered in our impairment evaluation of the investment when we committed to a plan to sell the investment during the fourth quarter of 2013, and accordingly did not impact earnings for the second quarter and first six months of 2014.