Goodwill and Other Intangible Assets (Tables)

12 Months Ended

Dec. 31, 2011

Goodwill and Other Intangible Assets [Abstract]

Acquired intangible assets subject to amortization

     Acquired intangible assets subject to amortization included in other assets and deferred charges as of December 31, 2011 and December 31, 2010 were as follows:

	December 31, 2011				December 31, 2010
(Millions of Dollars)		Gross Carrying Amount		Accumulated Amortization		Gross Carrying Amount		Accumulated Amortization
Patents and trademarks	$	6.2	$	4.0	$	6.2	$	3.5
Customer lists		2.7		1.5		2.7		1.2
	$	8.9	$	5.5	$	8.9	$	4.7