MATERIALS, SUPPLIES, AND INVENTORIES (Tables)

6 Months Ended

Jun. 30, 2018

Inventory Disclosure [Abstract]

Schedule of inventory

Our inventory consisted of:

(in millions)	June 30, 2018		December 31, 2017
Natural gas in storage	$	121.9	$	209.0
Materials and supplies	221.4		211.2
Fossil fuel	123.3		118.8
Total	$	466.6	$	539.0