Fair Value Measurements - Schedule of Changes in Level 3 Assets and Liabilities (Details) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Contingent Payment Arrangements
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period		$ 7.8	$ 31.5	$ 10.2	$ 59.3
Net (gains) losses	[1]	0.2	(13.8)	(2.2)	(41.6)
Purchases and issuances		0.0	6.5	0.0	6.5
Settlements and reductions		0.0	(17.5)	0.0	(17.5)
Balance, end of period		8.0	6.7	8.0	6.7
Net change in unrealized (gains) losses relating to instruments still held at the reporting date	[1]	0.2	(13.8)	(2.2)	(41.6)
Affiliate Equity Obligations
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period		35.6	16.8	62.3	21.5
Net (gains) losses		0.0	0.0	0.0	0.0
Purchases and issuances		9.7	49.6	39.8	65.0
Settlements and reductions		(18.3)	(8.1)	(75.1)	(28.2)
Balance, end of period		27.0	58.3	27.0	58.3
Net change in unrealized (gains) losses relating to instruments still held at the reporting date		$ 0.0	$ 0.0	$ 0.0	$ 0.0

[1] Accretion and changes to the Company’s contingent payment arrangements are recorded in Imputed interest expense and contingent payment arrangements.