Segment Reporting - ADJ EBITDA Reconciliations (Details) - USD ($) $ in Millions	3 Months Ended				6 Months Ended
	Jun. 30, 2023	Mar. 31, 2023	Jun. 30, 2022	Mar. 31, 2022	Jun. 30, 2023	Jun. 30, 2022
Net Income (Loss) Available to Common Stockholders, Basic	$ 178.7		$ 206.3		$ 361.5	$ 373.2
Net (loss) income attributable to noncontrolling interest	(0.7)	$ 0.1	0.4	$ 0.4	(0.6)	0.8
Preferred Stock Dividends, Income Statement Impact	14.4		14.4		28.7	28.7
Provision for income taxes	71.8		79.9		115.9	117.6
Interest Income (Expense), Nonoperating, Net	(98.8)		(68.5)		(193.8)	(132.1)
Depreciation and amortization	46.9		45.8		91.3	92.8
Other Nonoperating Income (Expense)	(0.8)		(1.2)		(10.9)	(2.3)
StockBasedCompensationExpenseEBITDA	10.9		14.5		21.3	22.0
MergerRelatedAndIntegrationCosts	10.9		13.4		30.4	39.0
Restructuring Costs	9.8				9.8
Adjusted EBITDA	442.3		444.4		863.0	808.5
Stock-based compensation expense	$ 12.2		15.8		23.9	24.7
Adjusted EBITDA Margin %	11.10%
Merger Related Stock Based Compensation Expense	$ 1.3		1.4		2.6	2.7
EES
Net Income (Loss) Available to Common Stockholders, Basic	167.0		222.8		338.3	401.5
Net (loss) income attributable to noncontrolling interest	(0.7)		0.1		(0.8)	0.4
Preferred Stock Dividends, Income Statement Impact	0.0		0.0		0.0	0.0
Provision for income taxes	0.0		0.0		0.0	0.0
Interest Income (Expense), Nonoperating, Net	0.0		0.0		0.0	0.0
Depreciation and amortization	11.5		11.2		21.4	23.2
Other Nonoperating Income (Expense)	9.8		1.4		10.3	(1.6)
StockBasedCompensationExpenseEBITDA	1.4		2.7		2.8	4.4
MergerRelatedAndIntegrationCosts	0.0		0.0		0.0	0.0
Restructuring Costs	0.0				0.0
Adjusted EBITDA	$ 189.0		$ 235.4		$ 372.0	$ 427.9
Adjusted EBITDA Margin %	8.60%		10.10%		8.60%	9.70%
CSS
Net Income (Loss) Available to Common Stockholders, Basic	$ 132.2		$ 130.6		$ 267.6	$ 234.3
Net (loss) income attributable to noncontrolling interest	0.1		0.0		0.3	0.0
Preferred Stock Dividends, Income Statement Impact	0.0		0.0		0.0	0.0
Provision for income taxes	0.0		0.0		0.0	0.0
Interest Income (Expense), Nonoperating, Net	0.0		0.0		0.0	0.0
Depreciation and amortization	17.9		17.9		35.9	36.0
Other Nonoperating Income (Expense)	27.7		(0.1)		28.5	0.5
StockBasedCompensationExpenseEBITDA	1.6		1.4		2.7	2.3
MergerRelatedAndIntegrationCosts	0.0		0.0		0.0	0.0
Restructuring Costs	0.0				0.0
Adjusted EBITDA	$ 179.5		$ 150.0		$ 335.0	$ 273.1
Adjusted EBITDA Margin %	9.70%		9.40%		9.30%	9.00%
UBS
Net Income (Loss) Available to Common Stockholders, Basic	$ 183.1		$ 161.8		$ 363.4	$ 291.8
Net (loss) income attributable to noncontrolling interest	0.0		0.0		0.0	0.0
Preferred Stock Dividends, Income Statement Impact	0.0		0.0		0.0	0.0
Provision for income taxes	0.0		0.0		0.0	0.0
Interest Income (Expense), Nonoperating, Net	0.0		0.0		0.0	0.0
Depreciation and amortization	6.4		5.7		12.4	11.5
Other Nonoperating Income (Expense)	(1.7)		(0.6)		(1.1)	0.6
StockBasedCompensationExpenseEBITDA	0.8		0.9		1.6	1.5
MergerRelatedAndIntegrationCosts	0.0		0.0		0.0	0.0
Restructuring Costs	0.0				0.0
Adjusted EBITDA	$ 188.6		$ 169.0		$ 376.3	$ 305.4
Adjusted EBITDA Margin %	11.10%		10.90%		11.20%	10.30%
Corporate Segment
Net Income (Loss) Available to Common Stockholders, Basic	$ (303.6)		$ (308.9)		$ (607.8)	$ (554.4)
Net (loss) income attributable to noncontrolling interest	(0.1)		0.3		(0.1)	0.4
Preferred Stock Dividends, Income Statement Impact	14.4		14.4		28.7	28.7
Provision for income taxes	71.8		79.9		115.9	117.6
Interest Income (Expense), Nonoperating, Net	98.8		(68.5)		193.8	132.1
Depreciation and amortization	11.1		11.0		21.6	22.1
Other Nonoperating Income (Expense)	(35.0)		(1.9)		(26.8)	2.8
StockBasedCompensationExpenseEBITDA	7.1		9.5		14.2	13.8
MergerRelatedAndIntegrationCosts	10.9		13.4		30.4	39.0
Restructuring Costs	9.8				9.8
Adjusted EBITDA	$ (114.8)		$ (110.0)		$ (220.3)	$ (197.9)