CONSOLIDATED STATEMENTS OF CHANGES IN OWNERS' EQUITY AND SERIES A PREFERRED STOCK - USD ($) $ in Millions	Total	Cumulative Effect, Period of Adoption, Adjustment [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Additional Paid-in Capital [Member] Cumulative Effect, Period of Adoption, Adjustment [Member]	Retained Earnings (Accumulated Deficit) [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Treasury Shares [Member]	Noncontrolling Interests [Member]	Series A Preferred Stock [Member]	Series A Preferred Stock [Member] Cumulative Effect, Period of Adoption, Adjustment [Member]
Balance at Dec. 31, 2018	$ 7,470.8		$ 0.2	$ 6,154.9		$ (130.4)	$ 94.3	$ (39.6)	$ 1,391.4
Balance (in shares) at Dec. 31, 2018			231,791,000					666,000
Series A Preferred Stock at Dec. 31, 2018										$ 245.7
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Compensation on equity grants	60.3			60.3
Distribution equivalent rights	(14.2)			(14.2)
Shares issued under compensation program (in shares)			1,397,000
Shares and units tendered for tax withholding obligations	(13.9)							$ (13.9)
Shares and units tendered for tax withholding obligations (in shares)			(344,000)					344,000
Series A Preferred Stock dividends
Preferred stock dividends	(91.7)					(91.7)
Dividends in excess of retained earnings				(91.7)		91.7
Deemed dividends - accretion of beneficial conversion feature	(33.1)			(33.1)						33.1
Common stock dividends
Common stock dividends	(846.8)					(846.8)
Dividends in excess of retained earnings				(846.8)		846.8
Distributions to noncontrolling interests	(294.7)								(294.7)
Contributions from noncontrolling interests	555.3								555.3
Sale of ownership interests in subsidiaries, net	1,611.5			(8.2)					1,619.7
Other comprehensive income (loss)	(1.8)						(1.8)
Net income (loss)	41.2					(209.2)			250.4
Balance at Dec. 31, 2019	8,442.9		$ 0.2	5,221.2		(339.6)	92.5	$ (53.5)	3,522.1
Balance (in shares) at Dec. 31, 2019			232,844,000					1,010,000
Series A Preferred Stock at Dec. 31, 2019										278.8
Balance at Dec. 31, 2018	7,470.8		$ 0.2	6,154.9		(130.4)	94.3	$ (39.6)	1,391.4
Series A Preferred Stock at Dec. 31, 2018										245.7
Balance at Dec. 31, 2019	8,442.9		$ 0.2	5,221.2		(339.6)	92.5	(53.5)	3,522.1
Series A Preferred Stock at Dec. 31, 2019										278.8
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Compensation on equity grants	66.2			66.2
Distribution equivalent rights	(5.4)			(5.4)
Shares issued under compensation program (in shares)			939,000
Shares and units tendered for tax withholding obligations	(5.9)							$ (5.9)
Shares and units tendered for tax withholding obligations (in shares)			(235,000)					235,000
Repurchases of common stock	(91.5)							$ (91.5)
Repurchases of common stock (in shares)			5,486,000					(5,486,000)
Series A Preferred Stock dividends
Preferred stock dividends	(91.7)					(91.7)
Dividends in excess of retained earnings				(91.7)		91.7
Deemed dividends - accretion of beneficial conversion feature	(37.6)
Deemed dividends - accretion of beneficial conversion feature / partial repurchase of Series A Preferred Stock	(39.2)			(39.2)						37.6
Common stock dividends
Common stock dividends	(282.0)					(282.0)
Dividends in excess of retained earnings				(282.0)		282.0
Partial repurchase of Series A Preferred Stock	(29.2)			(29.2)						(15.0)
Distributions to noncontrolling interests	(570.7)								(570.7)
Contributions from noncontrolling interests	41.5								41.5
Non-cash allocation to noncontrolling interests	27.5								27.5
Other comprehensive income (loss)	(234.3)						(234.3)
Net income (loss)	(1,325.0)					(1,553.9)			228.9
Balance at Dec. 31, 2020	5,903.2	$ (448.3)	$ 0.2	4,839.9	$ (448.3)	(1,893.5)	(141.8)	$ (150.9)	3,249.3
Balance (in shares) at Dec. 31, 2020			228,062,000					6,731,000
Series A Preferred Stock at Dec. 31, 2020										301.4	$ 448.3
Common stock dividends
Repurchases of common stock (in shares)			(5,486,000)					5,486,000
Non-cash allocation to noncontrolling interests	27.5								27.5
Balance at Dec. 31, 2019	8,442.9		$ 0.2	5,221.2		(339.6)	92.5	$ (53.5)	3,522.1
Series A Preferred Stock at Dec. 31, 2019										278.8
Balance at Dec. 31, 2020	5,903.2	(448.3)	$ 0.2	4,839.9	(448.3)	(1,893.5)	(141.8)	(150.9)	3,249.3
Series A Preferred Stock at Dec. 31, 2020										301.4	448.3
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Compensation on equity grants	59.2			59.2
Distribution equivalent rights	(3.1)			(3.1)
Shares issued under compensation program (in shares)			1,312,000
Shares and units tendered for tax withholding obligations	(13.2)							$ (13.2)
Shares and units tendered for tax withholding obligations (in shares)			(397,000)					397,000
Repurchases of common stock	(40.0)							$ (40.0)
Repurchases of common stock (in shares)			756,000					(756,000)
Series A Preferred Stock dividends
Preferred stock dividends	(87.3)					(87.3)
Dividends in excess of retained earnings				(87.3)		87.3
Common stock dividends
Common stock dividends	(91.5)					(91.5)
Dividends in excess of retained earnings				(91.5)		91.5
Distributions to noncontrolling interests	(449.1)								(449.1)
Contributions from noncontrolling interests	15.8								15.8
Other comprehensive income (loss)	(89.1)						(89.1)
Net income (loss)	422.1					71.2			350.9
Balance at Dec. 31, 2021	5,178.7		$ 0.2	4,268.9		(1,822.3)	(230.9)	$ (204.1)	3,166.9
Balance (in shares) at Dec. 31, 2021			228,221,000					7,884,000
Series A Preferred Stock at Dec. 31, 2021										749.7
Common stock dividends
Repurchases of common stock (in shares)			(756,000)					756,000
Balance at Dec. 31, 2020	$ 5,903.2	$ (448.3)	$ 0.2	$ 4,839.9	$ (448.3)	$ (1,893.5)	$ (141.8)	$ (150.9)	$ 3,249.3
Series A Preferred Stock at Dec. 31, 2020										$ 301.4	$ 448.3