Regulatory Assets and Liabilities and Regulatory Matters (Tables)

12 Months Ended

Sep. 30, 2012

Regulated Operations [Abstract]

Regulatory assets and liabilities associated with Gas Utility and Electric Utility

The following regulatory assets and liabilities associated with Utilities are included in our accompanying balance sheets at September 30:

	2012		2011
Regulatory assets:
Income taxes recoverable	$	103,172	$	97,947
Underfunded pension and postretirement plans	188,222		150,669
Environmental costs	16,812		19,547
Deferred fuel and power costs	11,602		12,163
Removal costs, net	12,718		12,313
Other	5,879		7,816
Total regulatory assets	$	338,405	$	300,455
Regulatory liabilities:
Postretirement benefits	$	13,147	$	11,476
Environmental overcollections	2,883		4,758
Deferred fuel and power refunds	4,435		6,578
State tax benefits — distribution system repairs	7,385		6,282
Other	494		736
Total regulatory liabilities	$	28,344	$	29,830