ARO Trust (Tables)

3 Months Ended

Mar. 31, 2019

Investments, Debt and Equity Securities [Abstract]

ARO Trust

Investments within the ARO Trust at fair value were as follows (in millions):

	March 31, 2019				December 31, 2018
	Amortized Cost Basis		Fair Value		Amortized Cost Basis		Fair Value
Money Market Funds	$	27.8	$	27.8	$	21.7	$	21.7
U.S. Equity Funds	50.5		68.9		46.4		56.8
International Equity Funds	23.8		25.6		21.9		21.4
Municipal Bond Funds	50.1		50.5		50.1		49.6
Total	$	152.2	$	172.8	$	140.1	$	149.5