Properties (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Properties
Cost	$ 1,739.5	$ 1,701.3
Less accumulated depreciation and amortization	1,294.3	1,226.3
Properties, net	445.2	475.0
Assets under capital lease, net	11.8	9.3
Assets under capital lease, accumulated depreciation	7.6	6.2
Software development and maintenance costs
Non-capitalizable software development and maintenance costs	123.7	128.7	131.2
Depreciation
Depreciation expense	127.3	139.1	121.1
Properties under lease with municipality
Properties
Properties, net	7.3	7.5
Land
Properties
Cost	68.6	69.8
Buildings
Properties
Cost	339.0	350.7
Data processing equipment
Properties
Cost	209.9	207.6
Data processing software
Properties
Cost	556.9	529.5
Data processing software | Acquired in business combinations
Properties
Cost	71.1
Properties, net	24.2	31.3
Furniture, fixtures and other equipment
Properties
Cost	441.3	425.0
Leasehold improvements
Properties
Cost	94.9	85.9
Construction-in-progress
Properties
Cost	28.9	32.8
Capitalized software development costs
Software development and maintenance costs
Capitalized software development costs	28.4	30.9	31.4
Amortization of capitalized software development costs	$ 31.4	$ 28.7	$ 26.8