Condensed Consolidated Statements Of Operations (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended				9 Months Ended
	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2012		Dec. 31, 2011
Income Statement [Abstract]
Revenues	$ 31,187		$ 30,839		$ 91,835		$ 91,035
Cost of Sales	(29,519)		(29,273)		(86,847)		(86,313)
Gross Profit	1,668		1,566		4,988		4,722
Operating Expenses	(1,183)		(1,047)		(3,334)		(3,135)
Litigation Charges	0		(27)		(60)		(145)
Gain on Business Combination	0		0		81		0
Total Operating Expenses	(1,183)		(1,074)		(3,313)		(3,280)
Operating Income	485		492		1,675		1,442
Other Income (Expense), Net	10		(2)		28		12
Interest Expense	(59)		(64)		(170)		(192)
Income Before Income Taxes	436		426		1,533		1,262
Income Tax Expense	(138)		(126)		(454)		(380)
Net Income	$ 298		$ 300		$ 1,079		$ 882
Earnings Per Common Share
Diluted	$ 1.24	[1]	$ 1.20	[1]	$ 4.49	[1]	$ 3.51	[1]
Basic	$ 1.27	[1]	$ 1.22	[1]	$ 4.58	[1]	$ 3.57	[1]
Dividends Declared Per Common Share	$ 0.20		$ 0.20		$ 0.60		$ 0.60
Weighted Average Common Shares
Diluted	240		251		240		252
Basic	235		246		236		247

[1] Certain computations may reflect rounding adjustments