Income Taxes (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Current:
Federal	$ 52.6	$ 7.3	$ (16.4)
State and local	7.9	5.1	1.2
Foreign	42.2	33.9	26.5
Total current	102.7	46.3	11.3
Deferred:
Federal	42.9	71.3	70.1
State and local	9.3	9.5	11.8
Foreign	(1.7)	(3.2)	1.4
Total deferred	50.5	77.6	83.8
Income taxes relating to continuing operations	153.2	123.9	94.6
Reconciliation of income taxes from continuing operations at federal statutory rate
Federal statutory income tax rate (as a percent)	35.00%	35.00%	35.00%
Income taxes relating to continuing operations at federal statutory rate of 35%	161.7	131.0	101.8
State and local income taxes, net of federal taxes	11.0	8.7	7.1
Non-U.S. income taxed at other rates	(19.0)	(16.1)	(12.6)
Other	(0.5)	0.3	(1.7)
Income taxes relating to continuing operations	153.2	123.9	94.6
Deferred Tax Assets
Accrued liabilities	72.1	61.8
Net operating loss carryforwards	16.0	13.7
Interest rate swap		3.1
Other	8.4	12.4
Total deferred tax assets	96.5	91.0
Valuation allowance	(18.2)	(14.6)
Net deferred tax assets	78.3	76.4
Deferred Tax Liabilities
Depreciation and amortization	(187.6)	(175.9)
Partnership investments	(253.0)	(219.0)
Convertible notes	(10.0)	(12.5)
Other	(3.5)	(1.3)
Total deferred tax liabilities	(454.1)	(408.7)
Net deferred tax liabilities	(375.8)	(332.3)
Income from continuing operations before income taxes of non-U.S. subsidiaries	170.6	134.7	117.0
Amount of total temporary difference related to the excess of financial reporting basis over tax basis in the non-U.S. subsidiaries on which U.S. federal income taxes are not provided	$ 711.0