Quarterly Financial Information (Unaudited) (Tables)

12 Months Ended

Dec. 31, 2020

Quarterly Financial Information Disclosure [Abstract]

Schedule of Quarterly Financial Information [Table Text Block]

The following table provides a summary of unaudited quarterly financial information:

	First Quarter		Second Quarter		Third Quarter		Fourth Quarter		Year
2020	(in millions, except per share amounts or otherwise specified)
Revenues	$	225.8	$	120.6	$	177.8	$	200.2	$	724.4
Operating income (loss)	$	(7.2)	$	(112.5)	$	(42.1)	$	(61.9)	$	(223.7)
Net income (loss)	$	367.4	$	(184.4)	$	(49.2)	$	(130.6)	$	3.2
Net gain (loss) from asset sales, inclusive of restructuring costs and impairment	$	3.7	$	—	$	0.1	$	(11.3)	$	(7.5)
Per share information
Basic EPS	$	1.54	$	(0.76)	$	(0.20)	$	(0.54)	$	0.01
Diluted EPS	$	1.54	$	(0.76)	$	(0.20)	$	(0.54)	$	0.01
Production information
Total equivalent production (Mboe)	7,930.9		7,972.9		7,057.0		7,364.1		30,324.9

2019
Revenues	$	280.6	$	296.2	$	307.5	$	321.9	$	1,206.2
Operating income (loss)	$	(15.8)	$	72.3	$	52.1	$	48.9	$	157.5
Net income (loss)	$	(116.7)	$	48.8	$	81.0	$	(110.4)	$	(97.3)
Net gain (loss) from asset sales, inclusive of restructuring costs and impairment	$	(18.2)	$	17.8	$	(2.1)	$	1.4	$	(1.1)
Per share information
Basic EPS	$	(0.49)	$	0.20	$	0.34	$	(0.46)	$	(0.41)
Diluted EPS	$	(0.49)	$	0.20	$	0.34	$	(0.46)	$	(0.41)
Production information
Total equivalent production (Mboe)	7,806.3		7,534.7		8,404.0		8,465.3		32,210.3