Consolidated Statements Of Comprehensive Income (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Mar. 31, 2012	Mar. 31, 2011	Mar. 31, 2012	Mar. 31, 2011
Consolidated Statements Of Comprehensive Income [Abstract]
Net Income Available for Common Stock	$ 67,392	$ 115,611	$ 128,091	$ 174,154
Other Comprehensive Income (Loss), Before Tax:
Foreign Currency Translation Adjustment			0	17
Reclassification Adjustment for Realized Foreign Currency Translation Loss in Net Income			0	34
Unrealized Gain on Securities Available for Sale Arising During the Period	3,116	897	3,828	3,438
Unrealized Gain (Loss) on Derivative Financial Instruments Arising During the Period	14,498	(40,844)	16,653	(67,980)
Reclassification Adjustment for Realized Gains on Derivative Financial Instruments in Net Income	(16,185)	(7,212)	(28,050)	(16,265)
Other Comprehensive Income (Loss), Before Tax	1,429	(47,159)	(7,569)	(80,756)
Income Tax Expense Related to Unrealized Gain on Securities Available for Sale Arising During the Period	1,161	337	1,424	1,298
Income Tax Expense (Benefit) Related to Unrealized Gain (Loss) on Derivative Financial Instruments Arising During the Period	840	(16,778)	1,657	(27,946)
Reclassification Adjustment for Income Tax Expense on Realized Gains from Derivative Financial Instruments in Net Income	(1,816)	(2,847)	(6,460)	(6,572)
Income Taxes - Net	185	(19,288)	(3,379)	(33,220)
Other Comprehensive Income (Loss)	1,244	(27,871)	(4,190)	(47,536)
Comprehensive Income	$ 68,636	$ 87,740	$ 123,901	$ 126,618