Investments (Tables)

12 Months Ended

Dec. 31, 2018

Equity Method Investments and Joint Ventures [Abstract]

Investments Reported in Other Current and Non-Current Assets

The following is a summary of our investments and the related funding commitments (in millions):

	December 31, 2018				December 31,
			Funding		2017
	Assets		Commitments		Assets
Chem-Mod LLC	$	4.0	$	—	$	4.0
Chem-Mod International LLC		2.0		—		2.0
Clean-coal investments:
Controlling interest in 6 limited liability companies that own 14 2009 Era Clean Coal Plants		5.1		—		10.2
Non-controlling interest in one limited liability companies that owns one 2011 Era Clean Coal Plant		0.4		—		0.6
Controlling interest in 17 limited liability companies that own 19 2011 Era Clean Coal Plants		43.0		—		58.5
Other investments		5.0		—		3.8
Total investments	$	59.5	$	—	$	79.1