Unconsolidated Entities - Summarized Financial Information of Co-Investment Ventures (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012
Schedule Of Equity Method Investments Joint Ventures [Line Items]
Revenues	$ 445.3	$ 336.3	$ 1,270.0	$ 1,048.2
Net earnings	66.7	(6.8)	145.6	(8.6)
Total assets	23,382.1		23,382.1		17,612.6
Amounts due to us	177.8		177.8		72.9
Third party debt	7,434.7		7,434.7		7,192.6
Total liabilities	9,562.8		9,562.8		8,186.7
Noncontrolling interest	12.3		12.3		8.9
Venture partners' equity	13,807.0		13,807.0		9,417.0
Our weighted average ownership	30.40%		30.40%		25.10%
Our investment balance	4,035.8		4,035.8		2,013.1
Deferred gains, net of amortization	394.9		394.9		329.6
Americas [Member]
Schedule Of Equity Method Investments Joint Ventures [Line Items]
Revenues	173.2	184.8	538.4	581.0
Net earnings	9.1	(20.6)	34.9	(66.5)
Total assets	8,433.4		8,433.4		9,070.4
Amounts due to us	38.3		38.3		31.9
Third party debt	3,277.2		3,277.2		3,835.5
Total liabilities	3,620.7		3,620.7		4,170.4
Noncontrolling interest	1.6		1.6		1.4
Venture partners' equity	4,811.1		4,811.1		4,898.6
Our weighted average ownership	23.50%		23.50%		23.20%
Our investment balance	1,211.3		1,211.3		1,111.8
Deferred gains, net of amortization	141.1		141.1		147.9
Europe [Member]
Schedule Of Equity Method Investments Joint Ventures [Line Items]
Revenues	215.3	115.5	571.6	361.4
Net earnings	41.9	9.6	77.8	49.0
Total assets	11,471.4		11,471.4		6,605.2
Amounts due to us	44.8		44.8		33.3
Third party debt	2,715.7		2,715.7		2,384.2
Total liabilities	4,409.7		4,409.7		2,953.8
Noncontrolling interest	10.7		10.7		7.5
Venture partners' equity	7,051.0		7,051.0		3,643.9
Our weighted average ownership	41.30%		41.30%		29.70%
Our investment balance	2,492.3		2,492.3		722.8
Deferred gains, net of amortization	184.3		184.3		181.6
Asia [Member]
Schedule Of Equity Method Investments Joint Ventures [Line Items]
Revenues	56.8	36.0	160.0	105.8
Net earnings	15.7	4.2	32.9	8.9
Total assets	3,477.3		3,477.3		1,937.0
Amounts due to us	94.7		94.7		7.7
Third party debt	1,441.8		1,441.8		972.9
Total liabilities	1,532.4		1,532.4		1,062.5
Venture partners' equity	1,944.9		1,944.9		874.5
Our weighted average ownership	15.10%		15.10%		19.20%
Our investment balance	332.2		332.2		178.5
Deferred gains, net of amortization	$ 69.5		$ 69.5		$ 0.1