Goodwill and Intangible Assets
 12 Months Ended
Dec. 31, 2019
Goodwill and Intangible Assets Disclosure [Abstract]  
Goodwill and Intangible Assets [Text Block] GOODWILL AND INTANGIBLE ASSETS

As a result of completing the sale of U.S. Water Services on March 26, 2019, there was no goodwill recorded as of December 31, 2019 ($148.5 million at December 31, 2018).

The balance of intangible assets, net, for the year ended December 31, 2019:
 
December 31,
2018

 
 Amortization
 
Other (b)
 
December 31,
2019

Millions
 
 
 
 
 
 
 
Intangible Assets
 
 
 
 
 
 
 
Definite-Lived Intangible Assets
 
 
 
 
 
 
 
Customer Relationships

$50.7

 
$(1.1)
 
$(49.6)
 
—

Developed Technology and Other (a)
7.5

 
(0.4)
 
(6.1)
 

$1.0

Total Definite-Lived Intangible Assets
58.2

 
(1.5)
 
(55.7)
 
1.0

Indefinite-Lived Intangible Assets
 
 
 
 
 
 
 
Trademarks and Trade Names
16.6

 
n/a
 
(16.6)
 
—

Total Intangible Assets

$74.8

 
$(1.5)
 
$(72.3)
 

$1.0

(a)
Developed Technology and Other includes land easements and trade names with finite lives.
(b) On March 26, 2019, ALLETE completed the sale of U.S. Water Services which resulted in the removal of the related intangible assets from the Consolidated Balance Sheet.

Amortization expense for intangible assets was $1.5 million for the year ended December 31, 2019 ($5.6 million for the year ended December 31, 2018). The remaining definite-lived intangible assets will continue to be amortized ratably through 2028.