Unconsolidated Entities - Summarized Financial Information of Co-Investment Ventures (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013
Schedule Of Equity Method Investments Joint Ventures [Line Items]
Revenues	$ 525.70	$ 445.30	$ 1,509.80	$ 1,270.00
Net operating income	408.00	341.30	1,159.60	950.00
Net earnings	85.5	66.7	244.7	145.6
Equity in earnings	27.2	25.8	77.1	57.9
Amounts due to us	132.4		132.4		164.0
Third party debt	7,865.10		7,865.10		7,712.50
Total liabilities	9,291.20		9,291.20		9,189.90
Our weighted average ownership	35.40%		35.40%		29.20%
Our investment balance	5,640.50		5,640.50		4,250.00
Deferred gains, net of amortization	429.3		429.3		431.1
Gain (Loss) on disposition of property			5.56	10.00
Americas [Member]
Schedule Of Equity Method Investments Joint Ventures [Line Items]
Revenues	204.20	173.20	551.10	538.40
Net operating income	154.40	126.60	405.80	393.90
Net earnings	24.4	9.1	16.9	34.9
Equity in earnings	8.9	1.7	0.1	15.0
Amounts due to us	11.9		11.9		10.3
Third party debt	3,309.40		3,309.40		2,999.10
Total liabilities	3,513.30		3,513.30		3,177.10
Our weighted average ownership	40.20%		40.20%		22.70%
Our investment balance	2,371.30		2,371.30		1,194.00
Deferred gains, net of amortization	120.3		120.3		139.6
Europe [Member]
Schedule Of Equity Method Investments Joint Ventures [Line Items]
Revenues	250.50	215.30	749.50	571.60
Net operating income	198.00	170.10	590.90	434.80
Net earnings	38.7	41.9	166.9	77.8
Equity in earnings	14.6	20.0	66.8	36.3
Amounts due to us	16.7		16.7		43.7
Third party debt	2,797.70		2,797.70		2,998.20
Total liabilities	3,822.50		3,822.50		4,113.60
Our weighted average ownership	38.80%		38.80%		39.00%
Our investment balance	2,893.60		2,893.60		2,703.30
Deferred gains, net of amortization	197.1		197.1		196.7
Asia [Member]
Schedule Of Equity Method Investments Joint Ventures [Line Items]
Revenues	71.00	56.80	209.20	160.00
Net operating income	55.60	44.60	162.90	121.30
Net earnings	22.4	15.7	60.9	32.9
Equity in earnings	3.7	4.1	10.2	6.6
Amounts due to us	103.8		103.8		110.0
Third party debt	1,758.00		1,758.00		1,715.20
Total liabilities	1,955.40		1,955.40		1,899.20
Our weighted average ownership	15.00%		15.00%		15.00%
Our investment balance	375.60		375.60		352.70
Deferred gains, net of amortization	$ 111.9		$ 111.9		$ 94.8