Stockholders' Equity (Changes in Accumulated Other Comprehensive Income (Loss) by Component) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Jun. 30, 2013	Jun. 30, 2012
Stockholders' Equity Attributable to Parent [Abstract]
Foreign Currency Translation Adjustment, Net of Tax, Beginning Balance	$ 136
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Gain (Loss) Arising During Period, Net of Tax	(61)	(41)
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Reclassification Adjustment Realized upon Sale or Liquidation, Net of Tax	0
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax	(61)	(41)
Foreign Currency Translation Adjustment, Net of Tax, Ending Balance	75
Cumulative Changes in Net Gain (Loss) from Cash Flow Hedges, Effect Net of Tax, Beginning Balance	(5)
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Net of Tax	1	0
Other Comprehensive Income (Loss), Reclassification Adjustment on Derivatives Included in Net Income, Net of Tax	0
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax	1	0
Cumulative Changes in Net Gain (Loss) from Cash Flow Hedges, Effect Net of Tax, Ending Balance	(4)
Pension and Other Postretirement Benefit Plans, Net of Tax, Beginning Balance	(196)
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Net Unamortized Gain (Loss) Arising During Period, Net of Tax	0
Other Comprehensive Income (Loss), Reclassification, Pension and Other Postretirement Benefit Plans, Net Transition Asset (Obligation), Recognized in Net Periodic Benefit Cost, Net of Tax	7
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax	7	6
Pension and Other Postretirement Benefit Plans, Net of Tax, Ending Balance	(189)
Accumulated Other Comprehensive Income (Loss), Net of Tax, Beginning Balance	(65)
Other Comprehensive Income (Loss), Before Reclassifications, Net of Tax, Portion Attributable To Parent	(60)
Other Comprehensive Income (Loss), Amounts Reclassified to Earnings, Net of Tax, Portion Attributable To Parent	7
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	(53)	(35)
Accumulated Other Comprehensive Income (Loss), Net of Tax, Ending Balance	$ (118)