Utility Regulatory Assets and Liabilities and Regulatory Matters (Tables)

12 Months Ended

Sep. 30, 2011

Utility Regulatory Assets and Liabilities and Regulatory Matters [Abstract]

Regulatory assets and liabilities associated with Gas Utility and Electric Utility

	2011		2010
Regulatory assets:
Income taxes recoverable	$	97.9	$	82.5
Underfunded pension and postretirement plans		150.7		159.2
Environmental costs		19.5		22.6
Deferred fuel and power costs		12.2		36.6
Removal costs, net		12.3		13.0
Other		7.8		5.8
Total regulatory assets	$	300.4	$	319.7
Regulatory liabilities:
Postretirement benefits	$	11.5	$	10.5
Environmental overcollections		4.7		7.2
Deferred fuel and power refunds		6.6		8.3
State tax benefits — distribution system repairs		6.3		6.7
Other		0.7		—
Total regulatory liabilities	$	29.8	$	32.7