Lease Obligations (Schedule Of Future Minimum Rental Payments For Operating Leases) (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2013
Leases, Operating [Abstract]
2014	$ 213
2015	165
2016	118
2017	90
2018	63
Thereafter	202
Total minimum lease payments (1)	$ 851	[1]

[1] Minimum lease payments have not been reduced by minimum sublease rentals of $33 million due under future noncancelable subleases.