Furniture, Equipment and Leasehold Improvements, net (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Property, Plant and Equipment [Abstract]
Furniture and equipment	$ 932.6	$ 881.5
Leasehold improvements	597.2	593.0
Land and buildings	109.9	111.6
Furniture, equipment and leasehold improvements	1,639.7	1,586.1
Less: Accumulated depreciation	(1,134.9)	(1,126.3)
Total furniture, equipment and leasehold improvements, net	504.8	459.8
Depreciation and amortization expense	$ 124.3	$ 130.7	$ 129.0