Quarterly Financial Data (Summary Of Quarterly Financial Information) (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Apr. 30, 2013	Jan. 31, 2013	Oct. 31, 2012	Jul. 31, 2012	Apr. 30, 2012	Jan. 31, 2012	Oct. 31, 2011	Jul. 31, 2011	Apr. 30, 2013	Apr. 30, 2012	Apr. 30, 2011
Quarterly Financial Information Disclosure [Abstract]
Revenues	$ 2,200,212	$ 471,979	$ 137,263	$ 96,489	$ 2,000,674	$ 663,280	$ 129,194	$ 100,623	$ 2,905,943	$ 2,893,771	$ 2,944,980
Income (loss) from continuing operations before taxes (benefit)	1,129,836	(96,268)	(162,288)	(169,269)	981,626	(1,026)	(203,929)	(200,601)	702,011	576,070	627,703
Income taxes (benefit)	440,914	(79,353)	(61,089)	(63,619)	389,923	2,541	(80,916)	(81,446)	236,853	230,102	235,156
Net income (loss) from continuing operations	688,922	(16,915)	(101,199)	(105,650)	591,703	(3,567)	(123,013)	(119,155)	465,158	345,968	392,547
Net income (loss) from discontinued operations	(24,582)	(793)	(4,044)	(1,791)	(5,600)	218	(18,711)	(55,943)	(31,210)	(80,036)	13,563
NET INCOME	664,340	(17,708)	(105,243)	(107,441)	586,103	(3,349)	(141,724)	(175,098)	433,948	265,932	406,110
Continuing operations (in usd per share	$ 2.53	$ (0.06)	$ (0.37)	$ (0.38)	$ 2.02	$ (0.01)	$ (0.41)	$ (0.39)	$ 1.70	$ 1.16	$ 1.27
Discontinued operations (in usd per share)	$ (0.09)	$ (0.01)	$ (0.02)	$ (0.01)	$ (0.02)		$ (0.06)	$ (0.18)	$ (0.11)	$ (0.27)	$ 0.04
Consolidated (in usd per share)	$ 2.44	$ (0.07)	$ (0.39)	$ (0.39)	$ 2.00	$ (0.01)	$ (0.47)	$ (0.57)	$ 1.59	$ 0.89	$ 1.31
Continuing operations (in usd per share)	$ 2.51	$ (0.06)	$ (0.37)	$ (0.38)	$ 2.01	$ (0.01)	$ (0.41)	$ (0.39)	$ 1.69	$ 1.16	$ 1.27
Discontinued operations (in usd per share)	$ (0.09)	$ (0.01)	$ (0.02)	$ (0.01)	$ (0.02)		$ (0.06)	$ (0.18)	$ (0.11)	$ (0.27)	$ 0.04
Consolidated (in usd per share)	$ 2.42	$ (0.07)	$ (0.39)	$ (0.39)	$ 1.99	$ (0.01)	$ (0.47)	$ (0.57)	$ 1.58	$ 0.89	$ 1.31
Goodwill impairments								$ 99,700	$ 0	$ 7,409	$ 22,700