Materials, Supplies, and Inventories (Tables)

6 Months Ended

Jun. 30, 2016

Inventory Disclosure [Abstract]

Schedule of inventory

Our inventory consisted of:

(in millions)	June 30, 2016		December 31, 2015
Materials and supplies	$	217.3	$	219.2
Fossil fuel	156.6		183.7
Natural gas in storage	120.6		284.1
Total	$	494.5	$	687.0