Capitalized Exploratory Well Costs (Tables)

6 Months Ended

Jun. 30, 2016

Capitalized Exploratory Well Costs [Abstract]

Capitalized Exploratory Well Costs [Table Text Block]

Net changes in capitalized exploratory well costs are presented in the table below. The balance at June 30, 2016, represents the amount of capitalized exploratory well costs that are pending the determination of proved reserves.

	Capitalized Exploratory Well Costs
	2016
	(in millions)
Balance at January 1,	$	2.6
Additions to capitalized exploratory well costs pending the determination of proved reserves	11.0
Reclassification to proved properties after the determination of proved reserves	—
Capitalized exploratory well costs charged to expense	(0.1		)
Balance at June 30,	$	13.5