CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) (unaudited) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Net income	$ 76.4	$ 33.9	$ 155.1	$ 38.3
Other comprehensive income (loss), before tax:
Foreign currency translation gain (loss)	2.3	(1.1)	2.6	0.4
Cash flow hedges:
Gains (losses) arising in period	(8.2)	40.7	(16.2)	32.9
Reclassification of losses (gains) to net income (loss)	(2.1)	14.5	(5.3)	27.7
Pension and OPEB plans:
Reclassification of prior service cost (credits) to net income (loss)	(13.6)	(13.8)	(27.0)	(27.6)
Reclassification of losses (gains) to net income (loss)	1.7	6.0	3.3	11.9
Other comprehensive income (loss), before tax	(19.9)	46.3	(42.6)	45.3
Income tax benefit related to items of comprehensive income (loss)	0.0	3.9	0.0	3.9
Other comprehensive income (loss)	(19.9)	42.4	(42.6)	41.4
Comprehensive income (loss)	56.5	76.3	112.5	79.7
Less: Comprehensive income attributable to noncontrolling interests	15.2	16.6	31.4	34.6
Comprehensive income (loss) attributable to AK Steel Holding Corporation	$ 41.3	$ 59.7	$ 81.1	$ 45.1