CONDENSED CONSOLIDATED STATEMENTS OF EQUITY (DEFICIT) (unaudited) - USD ($) $ in Millions	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Treasury Stock [Member]	Accumulated Deficit [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Noncontrolling Interests [Member]
Balance at Dec. 31, 2015	$ (595.6)	$ 1.8	$ 2,266.8	$ (2.0)	$ (3,057.0)	$ (187.2)	$ 382.0
Net income (loss)	38.3				3.7		34.6
Issuance of common stock	249.4	0.6	248.8
Share-based compensation	3.2		3.2
Purchase of treasury stock	(0.3)			(0.3)
Change in accumulated other comprehensive income (loss)	41.4					41.4
Net distributions to noncontrolling interests	(37.0)						(37.0)
Balance at Jun. 30, 2016	(300.6)	2.4	2,518.8	(2.3)	(3,053.3)	(145.8)	379.6
Balance at Dec. 31, 2016	90.7	3.1	2,855.4	(2.4)	(3,064.8)	(63.5)	362.9
Net income (loss)	155.1				123.7		31.4
Share-based compensation	5.5	0.1	5.4
Stock options exercised	0.5		0.5
Exchangeable notes exchange feature	21.3		21.3
Purchase of treasury stock	(3.0)			(3.0)
Change in accumulated other comprehensive income (loss)	(42.6)					(42.6)
Net distributions to noncontrolling interests	(41.9)						(41.9)
Balance at Jun. 30, 2017	$ 185.6	$ 3.2	$ 2,882.6	$ (5.4)	$ (2,941.1)	$ (106.1)	$ 352.4