DISCLOSURE OF OFFSETTING ASSETS AND LIABILITIES, COLLATERAL AND ENCUMBERED ASSETS, Collateral (Details) (USD $)	Mar. 31, 2015	Sep. 30, 2014
Collateral Received that Can be Resold or Repledged [Abstract]
Collateral we received that is available to be delivered or repledged	$ 2,146,076,000	$ 2,178,868,000
Collateral that we delivered or repledged	949,809,000	879,071,000
Value of margin securities pledged to clearing organizations	155,400,000	138,800,000
Securities reserve deposit required and made	$ 125,100,000	$ 116,500,000