Regulatory Assets and Liabilities (Tables)

12 Months Ended

Dec. 31, 2014

Regulatory Assets and Liabilities Disclosure [Abstract]

Regulatory assets and liabilities

Our regulatory assets and liabilities as of December 31 consist of:

	2014		2013
	(Millions of Dollars)
Regulatory Assets
Deferred unrecognized pension costs	$	629.5	$	537.6
Deferred income tax related	176.0		169.5
Escrowed electric transmission costs	146.0		126.8
Escrowed PTF	66.6		49.3
Escrowed conservation	58.0		66.9
Deferred plant related -- capital lease	42.3		56.5
Deferred environmental costs	45.9		47.0
Other, net	106.9		54.9
Total regulatory assets	$	1,271.2	$	1,108.5
Regulatory Liabilities
Deferred cost of removal obligations	$	741.1	$	724.5
Escrowed bad debt costs	30.1		64.6
Other, net	59.4		90.0
Total regulatory liabilities	$	830.6	$	879.1