Condensed Consolidated Statements Of Operations (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended				6 Months Ended
	Sep. 30, 2012		Sep. 30, 2011		Sep. 30, 2012		Sep. 30, 2011
Income Statement [Abstract]
Revenues	$ 29,850		$ 30,216		$ 60,648		$ 60,196
Cost of Sales	(28,130)		(28,569)		(57,328)		(57,040)
Gross Profit	1,720		1,647		3,320		3,156
Operating Expenses	(1,065)		(1,051)		(2,151)		(2,088)
Litigation Charges	(44)		(118)		(60)		(118)
Gain on Business Combination	0		0		81		0
Total Operating Expenses	(1,109)		(1,169)		(2,130)		(2,206)
Operating Income	611		478		1,190		950
Other Income, Net	10		6		18		14
Interest Expense	(55)		(64)		(111)		(128)
Income Before Income Taxes	566		420		1,097		836
Income Tax Expense	(165)		(124)		(316)		(254)
Net Income	$ 401		$ 296		$ 781		$ 582
Earnings Per Common Share
Diluted	$ 1.67	[1]	$ 1.18	[1]	$ 3.25	[1]	$ 2.31	[1]
Basic	$ 1.70	[1]	$ 1.20	[1]	$ 3.31	[1]	$ 2.35	[1]
Dividends Declared Per Common Share	$ 0.20		$ 0.20		$ 0.40		$ 0.40
Weighted Average Common Shares
Diluted	240		250		240		252
Basic	236		246		236		247

[1] Certain computations may reflect rounding adjustments