GOODWILL AND INTANGIBLE ASSETS (Tables)
 12 Months Ended
Dec. 31, 2019
Goodwill and Intangible Assets Disclosure [Abstract]  
Schedule of Goodwill [Table Text Block]
Changes in the carrying value of goodwill were as follows:
 
Chlor Alkali Products and Vinyls
 
Epoxy
 
Total
 
($ in millions)
Balance at January 1, 2018
$
1,832.9

 
$
287.1

 
$
2,120.0

Foreign currency translation adjustment
(0.3
)
 
(0.1
)
 
(0.4
)
Balance at December 31, 2018
1,832.6

 
287.0

 
2,119.6

Foreign currency translation adjustment
0.1

 
—

 
0.1

Balance at December 31, 2019
$
1,832.7

 
$
287.0

 
$
2,119.7
Schedule of Finite-Lived Intangible Assets [Table Text Block]
Intangible assets consisted of the following:
 
 
 
December 31,
 
 
 
2019
 
2018
 
Useful Lives
 
Gross Amount
 
Accumulated Amortization
 
Net
 
Gross Amount
 
Accumulated Amortization
 
Net
 
 
 
($ in millions)
Customers, customer contracts and relationships
10-15 Years
 
$
673.5

 
$
(260.9
)
 
$
412.6

 
$
675.2

 
$
(211.9
)
 
$
463.3

Trade name
5 Years
 
7.0

 
(6.0
)
 
1.0

 
7.0

 
(4.6
)
 
2.4

Acquired technology
7 Years
 
85.1

 
(51.8
)
 
33.3

 
85.4

 
(39.6
)
 
45.8

Other
10 Years
 
1.8

 
(0.6
)
 
1.2

 
0.7

 
(0.6
)
 
0.1

Total intangible assets
 
 
$
767.4

 
$
(319.3
)
 
$
448.1

 
$
768.3

 
$
(256.7
)
 
$
511.6