Equities Changes in Equity (Details) (USD $)	3 Months Ended			3 Months Ended					3 Months Ended
	Nov. 30, 2013	Nov. 30, 2012	Aug. 31, 2011	Nov. 30, 2013 Capital equity certificates [Member]	Nov. 30, 2012 Capital equity certificates [Member]	Nov. 30, 2013 Noncontrolling Interest [Member]	Nov. 30, 2012 Noncontrolling Interest [Member]	Aug. 31, 2011 Noncontrolling Interest [Member]	Nov. 30, 2013 Class B Preferred Stock [Member]	Sep. 03, 2013 Class B Preferred Stock [Member]
Schedule of Capitalization, Equity [Line Items]
Preferred Stock, Shares Outstanding										11,319,175
Preferred Stock, Redemption Amount										$ 283,000,000
Proceeds from Issuance of Preferred Stock, net of Issuance Costs	273,724,000								(273,700,000)
Preferred Stock Dividends Accrued	(10,160,000)	6,136,000
Equities Deconsolidated	(8,016,000)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stockholders' Equity Attributable to Parent	5,131,208,000		4,455,341,000
Net Income (Loss) Attributable to Parent	242,186,000	343,707,000
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	(434,000)	245,000
Retirements Of Equities	(2,520,000)	(2,378,000)
Dividends and equity retirement determination				2,520,000	2,378,000
Equity Certificates Issued During Period, Value, New Issues				45,000	14,240,000
Change in Accrued Dividends and Equities Payable	87,000,000	(147,091,000)
Stockholders' Equity, Other	642,000	3,431,000				637,000	1,146,000
Stockholders' Equity Attributable to Parent	5,542,195,000	4,663,737,000	4,455,341,000
Stockholders' Equity Attributable to Noncontrolling Interest	21,539,000							17,982,000
Net income attributable to noncontrolling interests	842,000	2,174,000
Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders
Stockholders' Equity Attributable to Noncontrolling Interest	$ 18,239,000	$ 21,302,000						$ 17,982,000
Preferred Stock, Dividend Rate, Percentage									7.875%